JP2007136569A - Vacuum chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detach a workpiece from a vacuum chuck by preventing the occurrence of deformation of a sucker in the vacuum chuck having the porous sucker and supplying liquid between a sucking surface and the workpiece. <P>SOLUTION: This vacuum chuck 10 is formed by sintering an aggregate made of granular powder of inorganic material and a binder connecting the aggregates to each other, and it includes the porous sucker 12, the surface of which is provided with a sucking surface 12 for sucking and holding a workpiece. A fluid guide passage 16 penetrating and communicating with the sucking surface 13 is formed in the interior of the porous sucker 12. Negative pressure air is supplied to the fluid guide passage 16 by a vacuum pump 24, thereby sucking and holding the workpiece to the sucking surface 13, and when positive pressure fluid is supplied to the fluid guide passage 16 from a pressurizing pump 32, the workpiece is detached from the vacuum chuck. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum chuck for holding a workpiece by vacuum suction.

  When a circuit pattern is formed on the surface of a semiconductor wafer made of silicon, a liquid crystal display (LCD) made of glass is processed, or machining such as cutting or grinding is performed on various workpieces, these substrates are covered. A vacuum chuck is used to hold a workpiece, that is, a workpiece by vacuum suction. As described in Patent Document 1, such a vacuum chuck includes an adsorbent made of a porous material and a metal base plate to which the adsorbent is joined. A plurality of grooves are formed in the base plate for supply. A channel for guiding a vacuum is formed by a groove formed in the base plate and an adsorbent bonded to the base plate by an adhesive or the like. By connecting this flow path to an external vacuum source, the surface of the porous adsorbent is brought into a negative pressure state lower than atmospheric pressure, that is, a vacuum state, and the workpiece is adsorbed and held on the surface of the adsorbent. .

The workpiece which is held by the vacuum chuck and has been subjected to the predetermined processing is removed from the vacuum chuck. In order to improve the processing efficiency, it is necessary to quickly remove the workpiece after processing from the vacuum chuck, that is, dechuck, so that a vacuum such as compressed air is supplied to the adsorbent to quickly release the vacuum. I have to.
JP 2001-341042 A

  When the workpiece is processed in a clean room, when the pressurized gas is supplied to the porous adsorbent to dechuck the workpiece from the vacuum chuck, the supplied pressurized gas is contained in the chuck. It will be scattered in the clean room together with foreign matter or particles. If the scattered particles adhere to the surface of the workpiece, the production yield of mass-produced products will decrease, so when removing the workpiece from the vacuum chuck, supply liquid such as water to the porous adsorbent Attempts were made to eject liquid from the surface of the adsorbent.

  However, since the liquid has a higher viscosity resistance than the gas, it is necessary to supply a high-pressure liquid to the adsorbent during digging. For this reason, in a conventional vacuum chuck in which an adsorbent is bonded to a base plate, when liquid is supplied to the adsorbent for dechucking, stress due to back pressure is concentrated at the junction between the adsorbent and the base plate. As a result, the adsorbent is peeled off from the base plate or the adsorbent is deformed.

  An object of the present invention is to prevent the occurrence of deformation of an adsorbent in a vacuum chuck having a porous adsorbent.

  An object of the present invention is to supply a liquid between the suction surface and the workpiece so that the workpiece can be detached from the vacuum chuck.

  The vacuum chuck according to the present invention is a vacuum chuck for vacuum-adsorbing a workpiece, and is formed by sintering a mixture of an aggregate made of a granular material of an inorganic material and a binder for connecting the aggregates to each other. A porous adsorbent having an adsorbing surface for adsorbing and holding a workpiece on the surface, and forming a fluid guide path that penetrates and communicates with the adsorbing surface inside the porous adsorbent. A communication port that communicates with the guide path and is connected to a vacuum supply source is formed in the porous adsorbent.

  The vacuum chuck of the present invention is characterized in that a pressurized fluid is supplied to the fluid guide path when the work piece held on the suction surface is separated from the suction surface.

  The vacuum chuck of the present invention is characterized in that the fluid guide path is formed in a lattice shape, a concentric circle shape, or a spiral shape inside the porous adsorbent.

  The vacuum chuck of the present invention is characterized in that the permeation amount of fluid in the central portion of the porous adsorbent is different from the permeation amount of fluid in the peripheral portion.

  In the vacuum chuck of the present invention, the fluid guide path is separated into a plurality of independent guide paths including a fluid guide path in the central portion of the adsorbent and a fluid guide path in the peripheral portion, and the workpiece is sucked onto the suction surface. When holding, a vacuum is supplied with a time difference between the independent guide paths.

  In the vacuum chuck of the present invention, the fluid guide path is separated into a plurality of independent guide paths including a fluid guide path in the central portion of the porous adsorbent and a fluid guide path in the peripheral portion, and a workpiece is provided on the suction surface. When adsorbed and held, the vacuum pressure supplied to each independent guide path is made different.

  According to the present invention, since the fluid guide path that allows fluid to permeate and communicate with the adsorption surface is formed inside the porous adsorbent, the strength of the inner wall surface that defines the fluid guide surface is increased, and the workpiece is adsorbed. Even when negative pressure air is supplied to the fluid guide path when adsorbed and held on the surface, deformation of the porous adsorbent is prevented. Further, even if the pressurized fluid is supplied to the fluid guide path when the work piece held on the suction surface is removed from the vacuum chuck, deformation of the porous adsorbent is prevented. Thereby, the durability of the porous adsorbent can be improved, and the processing accuracy of the workpiece that is adsorbed and held can be increased.

  The fluid guide path is formed in a lattice shape, a concentric circle shape, or a spiral shape so that a plurality of passages are in communication with each other and dispersed inside the porous adsorbent. When the workpiece is held by the suction surface, an adsorption force is applied to the entire workpiece.

  When holding the work piece, the amount of air permeation on the adsorption surface can be changed between the central part and the peripheral part, or the time for supplying the vacuum between the central part and the peripheral part can be different. Air is no longer sandwiched between the workpiece and the suction surface before completion. Thereby, internal strain does not occur in the work piece held by suction, and the processing accuracy can be improved by preventing the occurrence of internal strain.

  In order to make the air permeation amount different in the plurality of areas of the adsorption surface, the number of flow paths constituting the net-like or net-like fluid guide path, the width of the fluid guide path, or the respective areas are different. This is achieved by supplying different pressures.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A is a perspective view showing an appearance of a vacuum chuck according to an embodiment of the present invention, and FIG. 1B is a perspective view showing an appearance of a vacuum chuck according to another embodiment of the present invention. It is. 2A is an enlarged cross-sectional view taken along line 2A-2A in FIG. 1A, and FIG. 2B is a cross-sectional view taken along line 2B-2B in FIG.

  As shown in FIG. 1 (A), the vacuum chuck 10 has a plate-like base 11 and a porous adsorbent 12 joined to the surface by an adhesive, each of which has a quadrilateral shape as a whole. It has become. The base 11 is formed of a metal, and the porous adsorbent 12 is formed by sintering a mixture of an aggregate made of a granular material of an inorganic material and a binder that connects the aggregates. The back surface of the porous adsorbent 12 is adhered to the surface of the base 11, and the surface of the base 11 is an adsorption surface 13 that adsorbs the workpiece. The outer peripheral portion of the porous adsorbent 12 is sealed with a resin or the like to form a sealing layer 14, and fluid such as air does not permeate the outer peripheral portion of the porous adsorbent 12. Similarly, the bottom of the porous adsorbent 12 is sealed with a resin or the like to form a sealing layer 15.

  Inside the porous adsorbent 12, as shown in FIG. 2 (A), there is a fluid guide path 16 composed of a plurality of passages extending in the left-right direction and the up-down direction in the drawing and communicating with each other at intersections. The fluid guide paths 16 are formed in a lattice shape and are dispersedly formed inside the porous adsorbent 12. In this way, the fluid guide path 16 is a fluid guide path network having a net shape or a net shape, and is formed inside the porous adsorbent 12.

  The porous adsorbent 12 shown in FIG. 2 (A) is composed of 11 passages in which a fluid guide channel network, that is, a fluid guide channel 16 is formed in parallel with two outer peripheral sides in the left-right direction of the porous adsorbent 12. These are formed by 11 passages formed in parallel with the two outer peripheral sides in the vertical direction, and communicate with each other, so that the fluid guide passage 16 is a lattice-like fluid guide passage network as a whole. ing. The passages constituting each fluid guide passage 16 are arbitrarily set depending on the size of the porous adsorbent 12 and the like. The cross-sectional shape of the passages constituting the fluid guide path 16 is a quadrangle, the pitch P between the fluid guide paths 16 is set to be the same, and the width dimension D of the fluid guide paths 16 is also set to be almost the same. Yes.

  As shown in FIG. 2 (B), the portion of the thickness D1 between the fluid guide path 16 and the adsorption surface 13 constitutes an adsorption side region 17 between the fluid guide path 16 and the back surface of the porous adsorbent 12. The portion of the thickness D2 constitutes the support side region 18, and the portion of the thickness D3 between the suction side region 17 and the support side region 18 constitutes the flow path forming region 19, and each of these regions 17-19 Are integrally formed by sintering the mixture of the aggregate and the binder to form the porous adsorbent 12.

  As the aggregate constituting the porous adsorbent 12, a granular material made of an alumina abrasive or a silicon carbide abrasive used for a grinding wheel is used. When an alumina abrasive is used as an aggregate, brown alumina abrasive A, white alumina abrasive WA, light red alumina abrasive PA, powdered alumina abrasive HA, artificial emery grinding as defined in JIS R6111 A material AE and an alumina zirconia abrasive AZ can be used. When the silicon carbide abrasive is an aggregate, a black silicon carbide abrasive C and a green silicon carbide abrasive GC can be used. In addition, any inorganic material can be used as long as it is an abrasive used for grinding wheels such as natural diamond, artificial diamond, and corundum. As the binding material, vitrified or resinoid, cement, rubber, glass and the like used as a binding material for a grindstone can be used.

  The porous adsorbent 12 is entirely formed by forming a powder mixture having such an aggregate and a binder into a shape shown in the drawing mold and then heating and sintering in a sintering furnace. After the structure has air permeability and is sintered, the sealing layers 14 and 15 are formed of a sealing material such as a resin. In order to form the fluid guide path 16 inside the porous adsorbent body 12, when forming the powder mixture using a molding die, a shape corresponding to the fluid guide path network is formed inside the powder mixture. Embed the formed extinguishing material. This vanishing material is lost by the heat during sintering of the powder mixture, and a fluid guide path 16 in the form of a lattice is formed inside the porous adsorbent 12.

  The surface of the porous adsorbent 12 is an adsorbing surface 13 that adsorbs and holds the workpiece, and the size of the adsorbing surface 13 substantially corresponds to the size of the workpiece. The illustrated porous adsorbent 12 has a square shape corresponding to a square workpiece, but may have a rectangular shape corresponding to the shape of the workpiece. If the workpiece is a disc, As shown in FIG. 1 (B), the porous adsorbent 12 may have a disk shape, and the surface shape of the porous adsorbent 12 is set to an arbitrary shape corresponding to the workpiece.

  The porous adsorbent 12 is formed with first and second communication ports 21 and 22 communicating with the fluid guide path 16. The first communication port 21 opens on the back surface of the porous adsorbent 12, the second communication port 22 opens on the outer peripheral surface, and the first communication port 21 is connected to the connection port 23 formed on the base 11. Communicate. A vacuum pump 24 as a vacuum supply source is connected to the connection port 23 by a vacuum pipe 25, and a flow path opening / closing valve 26 and a pressure adjustment valve 27 are provided in the vacuum pipe 25. A pressure pump 32 as a pressurized fluid supply source that pressurizes and discharges the liquid in the liquid container 31 is connected to the second communication port 22 by a liquid pipe 33, and a flow path opening / closing valve is connected to the liquid pipe 33. 34 and a pressure regulating valve 35 are provided.

  Therefore, when the vacuum pump 24 is driven in a state where the workpiece W is disposed on the suction surface 13 of the vacuum chuck 10 as shown by a two-dot chain line in FIG. Permeate into the porous adsorbent 12 and the space between the adsorbing surface 13 and the workpiece W placed thereon becomes a vacuum state lower than atmospheric pressure, that is, a negative pressure state. It is sucked and held on the suction surface 13. At this time, as shown in FIG. 2 (A), the fluid guide passages 16 are distributed in a net-like manner in the porous adsorbent body 12 at approximately equal intervals in the horizontal direction and the vertical direction in the drawing. Therefore, there is no significant difference in the entire suction surface 13.

  After the processing such as cutting, grinding, or surface treatment on the workpiece W attracted and held by the vacuum chuck 10 is completed, a vacuum pump 24 is used to dechuck the workpiece W from the vacuum chuck 10. The supply of negative pressure air to the fluid guide path 16 is stopped, and the liquid such as water in the liquid container 31 is pressurized and supplied into the fluid guide path 16 by driving the pressurizing pump 32. The water supplied to the fluid guide path 16 passes through the porous suction side region 17 and is discharged from the suction surface 13, and the workpiece W is separated from the suction surface 13 and removed from the vacuum chuck 10. When the workpiece W is removed from the vacuum chuck 10, that is, the dechuck is performed by discharging a liquid such as water from the suction surface 13, even if the vacuum chuck 10 is used in a clean room, it is removed from the suction surface 13. Compared to the case where compressed air is discharged, foreign matter, that is, particles do not scatter in the clean room. As a result, it is possible to prevent a decrease in accuracy of a mass-produced product and a decrease in manufacturing yield due to adhesion of foreign matter to the surface of the workpiece.

  The pressure of the water supplied to the fluid guide path 16 when the workpiece W is dechucked is higher in the viscosity resistance of the liquid when permeating through the porous body than the gas. Therefore, it is necessary to set the differential pressure with respect to the atmospheric pressure larger than the negative pressure air supplied to the fluid guide path 16. As described above, at the time of dechucking, a high-pressure liquid is supplied into the fluid guide path 16, but the fluid guide path 16 is formed inside the integrally formed porous adsorbent body 12 and supports the suction side region 17. Since the side area 18 and the flow path forming area 19 are systematically connected integrally, the strength of the wall surface defining the fluid guide path 16 is increased, and the deformation of the porous adsorbent 12 during the dechucking is prevented. The Therefore, as compared with the conventional case where a groove is formed on the surface of the base and the porous adsorbent is bonded to the base with an adhesive to form a vacuum chuck, the porous adsorbent 12 at the time of dechucking is formed. There is no occurrence of deformation or peeling of the porous adsorbent 12 from the base 11, the processing accuracy of the workpiece is increased, and the durability of the porous adsorbent 12 is greatly improved.

  3A is a sectional view showing a vacuum chuck 10 according to another embodiment of the present invention, and FIG. 3B is a sectional view taken along line 3B-3B in FIG. 3A. This vacuum chuck 10 has a base 11 and a porous adsorbent 12 as shown in FIG. 2, and each has a quadrilateral shape. In the plurality of passages formed in the porous adsorbent body 12 shown in FIG. 3A in parallel in the left-right direction in the drawing, the pitch P between them is a central portion rather than the peripheral portion of the porous adsorbent body 12. Is set smaller. Similarly, in the plurality of passages formed in parallel in the vertical direction, the pitch P between them is set to be smaller in the central portion than in the peripheral portion of the porous adsorbent. As a result, the fluid guide paths 16 are dispersed and formed as a whole in a lattice shape or a net shape, and the area occupied by the fluid guide paths 16 in the central portion of the porous adsorbent 12 is larger than the area occupied by the fluid guide paths 16 in the peripheral portion. Is also getting bigger.

  Accordingly, when a vacuum is supplied to the fluid guide path 16 when the workpiece W is adsorbed, more air flows from the central portion of the adsorption surface 13 into the porous adsorbent 12 than in the peripheral portion. Since the permeation amount is larger than that in the peripheral portion, the degree of vacuum between the suction surface 13 and the workpiece W reaches a predetermined value earlier in the central portion than in the peripheral portion. As described above, when the air permeability of the central portion of the porous adsorbent 12 is increased, when the workpiece W is adsorbed and held on the adsorption surface 13, first, the workpiece W has high air permeability, that is, the permeation amount is high. The vacuum is first sucked from the central portion where the vacuum suction force is high, and then sucked toward the periphery so as to push out the air sandwiched between the workpiece W and the suction surface 13. If the peripheral part is first adsorbed on the adsorption surface 13 and then the central part is adsorbed, there is a risk that distortion will occur inside the workpiece W that is adsorbed and held. By increasing the permeation amount of the pressurized air from the periphery, air is not taken in between the suction surface 13 and the workpiece W even during the suction, so that the workpiece W is distorted inside. It is held on the suction surface 13 without being generated.

  As shown in FIG. 3B, a common pipe 36 is connected to the connection port 23 formed in the base 11 so as to communicate with the communication port 21 formed in the porous adsorbent body 12. The vacuum pipe 25 and the liquid pipe 33 are connected via the switching valve 37. Therefore, in this case, negative pressure air and pressurized liquid can be supplied to the fluid guide path 16 via the common pipe 36. However, similarly to the case shown in FIG. 2B, the communication port 22 may be formed by opening on the outer peripheral surface of the porous adsorbent 12, and the liquid pipe 33 may be connected to the communication port 22. 3B, members having the same functions as the members constituting the negative pressure air supply circuit and the pressurized fluid supply circuit shown in FIG. 2B are denoted by the same reference numerals. Yes.

  4A is a sectional view showing a vacuum chuck 10 according to another embodiment of the present invention, and FIG. 4B is a sectional view taken along line 4B-4B in FIG. 4A. This vacuum chuck 10 has a base 11 and a porous adsorbent 12 similar to those shown in FIGS. 2 and 3, each having a quadrilateral shape.

  In the porous adsorbent 12 shown in FIG. 4A, a lattice-like fluid guide path 16a in the central portion of the porous adsorbent 12 and a fluid guide path 16b in the peripheral portion are separated from each other. It is formed as an independent guideway. Communication ports 21a and 21b are formed in the porous adsorbent body 12 so as to communicate with the respective fluid guide paths 16a and 16b, and connection ports 23a and 23b communicating with the respective communication ports are formed in the base 11. Similar to the case shown in FIG. 3, common pipes 36a and 36b are connected to the respective connection ports 23a and 23b, and the vacuum pipe 25 and the liquid pipe 33 are connected to the respective common pipes 36a and 36b via switching valves 37a and 37b. And are connected.

  As shown in FIG. 4, inside the porous adsorbent 12, separate fluid guide paths 16a and 16b are dispersed and formed in a net shape so as to be separated and independent at the central portion and the peripheral portion. Therefore, as shown in FIG. 4B, the pressure of the negative pressure air supplied to the fluid guide path 16a via the communication port 21a is regulated by the pressure regulating valve 27a, and the fluid guide path 16b via the communication port 21b. When the pressure of the negative pressure air supplied to the pressure is regulated by the pressure regulating valve 27b, the degree of vacuum of the negative pressure air supplied to the center fluid guide passage 16a is supplied to the peripheral fluid guide passage 16b. The degree of vacuum of the negative pressure air can be increased.

  Thus, like the porous adsorbent 12 shown in FIG. 3, when adsorbing the workpiece W, more air than the peripheral portion is present from the central portion of the adsorbing surface 13 to the inside of the porous adsorbent 12. Since the air flows in, the air permeation amount in the central portion is larger than that in the peripheral portion, and the degree of vacuum between the suction surface 13 and the workpiece W reaches the predetermined value earlier in the central portion than in the peripheral portion. When the air permeability of the central portion of the porous adsorbent 12 is thus increased, when the workpiece W is adsorbed and held on the adsorption surface 13, first, the workpiece W is highly breathable, that is, highly permeable and vacuum suctioned. It is first adsorbed from the central part where the force is high, and then adsorbed toward the periphery so as to push out the air sandwiched between the workpiece W and the adsorption surface 13. As a result, the workpiece W is held on the suction surface 13 without causing distortion inside.

  As shown in FIG. 4, when the fluid guide channel 16 is separated into a central fluid guide channel 16a and a peripheral fluid guide channel 16b, negative pressure air of the same pressure is supplied from the vacuum pump 24 to each. However, if negative pressure air is supplied to the fluid guide passage 16a in the central portion earlier than the fluid guide passage 16b in the peripheral portion, the workpiece W starts from the central portion first as in the case described above. It is adsorbed and then adsorbed toward the periphery so as to push out the air sandwiched between the workpiece W and the adsorption surface 13. As described above, when a vacuum is supplied to both the fluid guide paths 16a and 16b with a time difference, a flow path switching signal is sent from the control unit 39 to each of the switching valves 37a and 37b.

  FIG. 5 is a sectional view showing a vacuum chuck 10 according to another embodiment of the present invention. As shown in FIG. 1B, the vacuum chuck 10 has a base 11 and a porous adsorbent 12 each having a circular shape. Inside the porous adsorbent 12, concentric fluid guide paths 16 are formed in a dispersed manner, and the fluid guide path 16 is concentric fluid guide paths 16a in the central portion of the porous adsorbent 12. And the concentric fluid guide path 16b in the peripheral portion, and the fluid guide paths 16a and 16b are independent guide paths separated from each other. A plurality of concentric fluid guide paths constituting the fluid guide path 16a communicate with each other by a radial communication path 16c to form a fluid guide path network, and a plurality of concentric fluid guides constituting the fluid guide path 16b. The paths communicate with each other by a radial communication path 16c to form a fluid guide path network.

  A communication port 21a communicating with the fluid guide path 16a is formed in the porous adsorbent body 12, and a communication port 21b communicating with the fluid guide path 16b is formed in the porous adsorbent body 12, each as in FIG. 4B. The communication port is connected to a connection port formed on a base (not shown). The structures of the negative pressure air supply circuit and the pressurized fluid supply circuit in the vacuum chuck 10 shown in FIG. 5 are the same as those shown in FIG.

  The pitches in the radial direction of the concentric fluid guide paths in each of the fluid guide paths 16a and 16b are set to be the same, but the width dimension R1 of the fluid guide path 16a in the center portion is concentric fluid guide in the peripheral portion. It is set larger than the width dimension R2 of the path 16b. Therefore, like the porous adsorbent 12 shown in FIG. 3, when adsorbing the workpiece W, more air flows from the central portion of the adsorbing surface 13 into the porous adsorbent 12 than the peripheral portion. In addition, since the air permeation amount is larger than that in the peripheral portion, the degree of vacuum between the suction surface 13 and the workpiece W reaches a predetermined value earlier in the central portion than in the peripheral portion. When the air permeability, that is, the permeability of the central portion of the porous adsorbent 12 is increased as described above, when the work W is sucked and held on the sucking surface 13, the work W is first of high air permeability and vacuum suction. It is first adsorbed from the central part where the force is high, and then adsorbed toward the periphery so as to push out the air sandwiched between the workpiece W and the adsorption surface 13.

  Although the fluid guide path 16 shown in FIG. 5 is formed concentrically, the fluid guide path may be formed in a spiral shape. Also in that case, as shown in FIG. 5, it may be formed separately into a plurality of fluid guide paths 16a and 16b.

  In each of the vacuum chucks 10 described above, since the fluid guide path is formed inside the integrally formed porous adsorbent body 12, the fluid guide path is formed between the porous adsorbent body 12 and the base 11. The strength of the porous adsorbent 12 can be increased as compared with the case where the negative pressure air for adsorbing and holding the workpiece is supplied to the fluid guide path, and the pressure is high when the workpiece is dechucked. Even if a liquid such as water is supplied to the fluid guide path, deformation of the porous adsorbent 12 can be prevented. However, depending on the usage environment of the vacuum chuck, compressed air may be supplied without supplying liquid to the fluid guide path for dechucking. Further, the vacuum chuck 10 may supply only the negative pressure air for adsorbing and holding the fluid guide path without supplying the pressurized fluid to the fluid guide path when the workpiece is dechucked.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention. For example, as shown in FIG. 2, even when fluid guide channels having the same width are formed in the porous adsorbent body 12 at an equal pitch, the width of the fluid guide channel in the central part is set larger than that in the peripheral part. The function at the time of adsorption holding similar to FIG. 3 may be achieved. Moreover, in the porous adsorbent shown in FIG. 4 and FIG. 5, the fluid guide path in the central part and the fluid guide path in the peripheral part are divided into two, but it is divided into three or more parts from the central part toward the peripheral part. The fluid guide path may be formed separately and independently. Further, in the case of the vacuum chuck 10, the suction surface 13 is shown facing upward, and the workpiece W is supported on the upper surface of the vacuum chuck 10. It may be used with the surface 13 facing downward to support the workpiece W on the lower surface.

(A) is a perspective view which shows the external appearance of the vacuum chuck which is one embodiment of this invention, (B) is a perspective view which shows the external appearance of the vacuum chuck which is other embodiment of this invention. (A) is the 2A-2A line expanded sectional view in FIG. 1 (A), (B) is the 2B-2B sectional view taken on the line in FIG. 2 (A). (A) is sectional drawing which shows the vacuum chuck which is other embodiment of this invention, (B) is the 3B-3B sectional view taken on the line in FIG. 3 (A). (A) is sectional drawing which shows the vacuum chuck which is other embodiment of this invention, (B) is the 4B-4B sectional view taken on the line in FIG. 4 (A). It is sectional drawing which shows the vacuum chuck which is other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vacuum chuck 11 Base 12 Porous adsorption body 13 Adsorption surface 14, 15 Sealing layer 16 Fluid guide path 17 Adsorption side area 18 Support side area 19 Flow path formation area 21, 22 Communication port 23 Connection port 24 Vacuum pump (vacuum supply) source)
25 Vacuum piping 31 Liquid container 32 Pressurizing pump (pressurized fluid supply source)
33 Liquid piping

Claims (6)

A vacuum chuck for vacuum-sucking a workpiece,
A porous adsorbent formed by sintering a mixture of an aggregate composed of granular material of inorganic material and a binder for connecting the aggregates, and having an adsorption surface for adsorbing and holding a workpiece on the surface Have
Forming a fluid guide path that penetrates and communicates with the adsorption surface inside the porous adsorbent;
A vacuum chuck characterized in that a communication port communicating with the fluid guide path and connected to a vacuum supply source is formed in the porous adsorbent.   2. The vacuum chuck according to claim 1, wherein a pressurized fluid is supplied to the fluid guide path when the work piece held by the suction surface is separated from the suction surface.   3. The vacuum chuck according to claim 1, wherein the fluid guide path is formed in the porous adsorbent so as to be dispersed in a lattice shape, a concentric circle shape, or a spiral shape.   4. The vacuum chuck according to claim 1, wherein a permeation amount of fluid in a central portion of the porous adsorbent is different from a permeation amount of fluid in a peripheral portion. 5.   5. The vacuum chuck according to claim 1, wherein the fluid guide path is divided into a plurality of independent guide paths including a fluid guide path in a central portion of the adsorbent and a fluid guide path in a peripheral portion. A vacuum chuck for supplying a vacuum with a time difference between the independent guide paths when the workpiece is sucked and held on the suction surface.   The vacuum chuck according to any one of claims 1 to 4, wherein the fluid guide path is formed into a plurality of independent guide paths including a fluid guide path in a central portion of the porous adsorbent and a fluid guide path in a peripheral portion. A vacuum chuck characterized in that when the workpiece is separated and held on the suction surface by suction, the vacuum pressure supplied to each independent guide path is made different.

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