JP4694400B2 - Wafer holding device - Google Patents

Description

  The present invention relates to, for example, a wafer holding device that holds a wafer with a surface inspection device that rotates the wafer to inspect the surface in a semiconductor manufacturing process, and a device that generates or coats a film on the surface by rotating the wafer. The present invention relates to a wafer holding device that can hold a wafer and can be rotated in a holding state, such as a wafer holding device for holding.

  Conventionally, for example, a surface inspection apparatus that inspects a surface by rotating a wafer, a semiconductor that exposes and transfers a circuit pattern to a photosensitive agent (photoresist) formed or coated on the surface of a wafer by irradiating light 2. Description of the Related Art There are known wafer holding apparatuses that can hold a wafer and can rotate while being held in an exposure apparatus, a wafer transfer apparatus that transfers the wafer while holding the wafer, and the like.

  As such a wafer holding device, as shown in FIG. 8, a wafer holding device having a configuration in which the vicinity of the center of the wafer 1 is sucked and held on the circular chuck base 2 by using the suction force by vacuum evacuation on the back surface side. There is. In this case, since the contact area between the chuck base 2 and the wafer 1 is increased and bending occurs in the vicinity of the periphery of the wafer 1, a ring-shaped wafer seat is provided at the peripheral portion of the chuck base, and vacuum evacuation is performed. A wafer holding device configured to hold the wafer by adsorbing the vicinity of the periphery of the wafer to the wafer seat with a suction force (fixing means to the wafer seat) has been considered (for example, see Patent Document 1).

  In the wafer holding device disclosed in Patent Document 1, since the wafer seat is configured to hold the wafer by adsorbing the vicinity of the peripheral edge of the wafer using the suction force generated by vacuum evacuation, the wafer, the chuck base, and the wafer receiving device are configured. There is a possibility that the pressure in the facing space partitioned by the seat is lowered by the vacuum exhaust at the wafer seat and the wafer is bent. For this reason, a wafer holding device in which an opening passage for opening the facing space to the outside is provided on the chuck base is considered (for example, see Patent Document 2).

  As in the wafer holding devices of Patent Document 1 and Patent Document 2, in the structure in which the wafer is sucked to the chuck base or the wafer seat by the suction force by vacuum exhaust, the wafer is blown by blowing air on the surface of the wafer. Has been conceived of a wafer holding device configured to prevent the substrate from being bent and to be surely attracted to the chuck base or the wafer seat (see, for example, Patent Document 3).

  In general, in a wafer holding apparatus, dust or the like may be wound up by contact with the wafer. Therefore, a plurality of holding claws (fixing means to the wafer seat) are spaced around the periphery of the chuck base in the circumferential direction. A wafer holding device that can hold the wafer while reducing the contact area with the wafer by holding the peripheral edge of the wafer from a plurality of directions with the holding claws is considered (for example, Patent Document 4). , See Patent Document 5 and Patent Document 6.)

  Here, as described above, in the wafer holding device configured such that the wafer is fixed to the wafer seat provided on the chuck table, a facing space is formed between the chuck table and the wafer facing each other. However, when the chuck base is rotated to rotate the wafer, a centrifugal force acts on the air existing in the opposing space, resulting in a pressure deviation in which the vicinity of the wafer has a high pressure and the vicinity of the center of the wafer has a low pressure. Arise. This pressure deviation in the facing space causes the wafer to bend such that the vicinity of the center is closest to the platform and the vicinity of the periphery is farthest from the platform.

For this reason, for the purpose of eliminating the bending of the wafer due to the pressure deviation of the facing space, an air supply port for blowing air into the wafer from the back surface side and an air exhaust port for communicating the facing space with the outside are provided on the chuck base. A wafer holding device provided on a board is considered (for example, see Patent Document 7). Note that the wafer holding device of Patent Document 7 is configured to fix the wafer to the wafer seat (fixing means) using the suction force by vacuum exhaust, and reduce the amount of vacuum exhaust at the time of fixing. Therefore, a plurality of suction ports are interspersed on the wafer seat, and the wafer is sucked by each suction port.
JP 2003-324143 A Japanese Patent Laid-Open No. 10-218364 JP 2000-243814 A JP 2002-319613 A JP 2004-111903 A JP 2004-267404 A JP 2001-243814 A

  However, in the wafer holding device of Patent Document 7, it is possible to reduce the pressure deviation in which the vicinity of the periphery of the wafer is high pressure and the vicinity of the center of the wafer is low pressure in the facing space, but it is difficult to eliminate the pressure deviation. .

  For this reason, in the wafer, a plurality of fixing means (in Patent Document 7, vacuum exhaust from a plurality of suction ports is the same, but a plurality of holding claws are also the same). While the vicinity faces the chuck base at a predetermined interval, the vicinity of the portion not fixed to the wafer seat by each fixing means faces the chuck base at a larger interval than the above-mentioned predetermined interval. It becomes. In other words, in the vicinity of the peripheral edge of the wafer, a wave-like bend is formed in which the distance from the chuck base plate increases or decreases when viewed in the circumferential direction. For example, when viewed optically, this bending causes a shift in focal length in a scene where the optical axis is in a direction orthogonal to the wafer surface (Z direction), and the optical axis is inclined with respect to the wafer surface. In the case of the direction, there is a risk of causing a deviation in the X-Y direction at the irradiation position. For this reason, for example, when the surface of the wafer is inspected by spiral scanning, an error occurs in the inspection result, and when the semiconductor exposure is performed, the circuit pattern cannot be exposed and transferred to an appropriate position.

  The present invention has been made in view of the above circumstances, and provides a wafer holding device capable of holding a wafer without causing the wafer to bend even when the chuck base is rotated to rotate the wafer. It is intended to do.

In order to solve the above-described problem, the wafer holding device according to claim 1 is provided with a ring-shaped wafer seat along a peripheral portion of a disk-shaped chuck base that is rotatably supported. A wafer holding device capable of holding the wafer by fixing a peripheral portion of the wafer placed on the wafer seat to the wafer seat by a plurality of fixing means, and detecting a rotation speed of the chuck base The wafer receiving portion is provided with detecting means, and the fixing means are provided at intervals in the circumferential direction. Between the fixing means, the wafer fixed to the wafer receiving portion and the chuck base a plurality of communication holes for communicating the opposing space between the panel to the outside is provided inward of the wafer seat when viewed in the radial direction of the chuck base block a peripheral portion of the chuck base block, Each communication hole has the pair. Is connected to suction means for sucking the air in the space, said suction means, the amount of suction and wherein Rukoto be adjusted according to the rotational speed of the chuck base block.

The wafer holding device according to claim 2 is the wafer holding device according to claim 1 , wherein each of the fixing means and each of the communication holes are alternately arranged at equal intervals when viewed in the circumferential direction of the wafer. Each of the communication holes is disposed at an equal position when viewed in the radial direction of the wafer.

A wafer holding device according to a third aspect is the wafer holding device according to the first or second aspect , wherein the chuck base plate has a blow-out hole that communicates the opposed space with the outside in a radial direction. And a supply means for supplying air to the opposed space is connected to the blowout hole.

The wafer holding device according to claim 4 is the wafer holding device according to claim 3 , wherein the supply means adjusts the supply amount according to the rotational speed of the chuck base plate detected by the detection means. It is characterized by being.

The wafer holding device according to claim 5 is the wafer holding device according to any one of claims 1 to 4 , wherein the chuck base includes a centrifugal force accompanying rotation of the chuck base. Auxiliary wings are provided to suppress the air in the facing space from heading toward the peripheral edge of the chuck base by the action of.

The wafer holding device according to claim 6 is the wafer holding device according to claim 5 , wherein the auxiliary wing is a protrusion provided on at least one surface of the chuck base plate facing the wafer. Each of the protrusions is formed into a spiral shape toward the rotation center of the chuck base.

The wafer holding device according to claim 7 is the wafer holding device according to any one of claims 1 to 6 , wherein each of the fixing means is capable of contacting a peripheral edge of the wafer. Each of the holding claws is provided on the chuck base plate so as to be movable in a radial direction of the chuck base plate, and each of the holding claws contacts the peripheral edge of the wafer to press the wafer against the wafer seat. It is characterized by being pinched while being held.

  According to the first aspect of the present invention, in the vicinity of the peripheral portion of the wafer in the facing space between the wafer and the chuck base, the suction means has the communication hole for the air between the fixing means viewed in the circumferential direction. Therefore, even if the chuck base is rotationally driven, it is possible to prevent the air pressure between the fixing means from increasing. For this reason, it is possible to prevent a bend in the vicinity of the periphery of the wafer from being increased or decreased as viewed in the circumferential direction.

According to the first aspect of the present invention, the amount of air sucked by the suction means can be adjusted according to the rotational speed of the chuck base, that is, according to the centrifugal force acting on the air in the facing space. Further, it is possible to more appropriately prevent the air pressure between the fixing means in the vicinity of the peripheral edge of the wafer from increasing.

According to the second aspect of the present invention, since the suction means can suck the air at the intermediate position of each fixing means in the vicinity of the peripheral edge of the wafer in the opposed space to reduce the pressure, the vicinity of the peripheral edge of the wafer can be further reduced. It can be in a flat state.

According to the third aspect of the present invention, since the pressure in the vicinity of the center of the wafer can be increased in the facing space, the wafer can be made flatter.

According to the invention described in claim 4 , the supply amount of air from the supply means is adjusted according to the rotation amount of the chuck base, that is, according to the centrifugal force acting on the air in the opposed space. Therefore, the wafer can be more appropriately flattened.

According to the fifth aspect of the present invention, the auxiliary wing reduces the pressure deviation in which the pressure near the periphery of the wafer increases and the pressure near the center of the wafer decreases in the facing space when the chuck base is driven to rotate. Let For this reason, the auxiliary wing can assist the function of each suction means and each fixing means.

According to the sixth aspect of the present invention, since the centripetal force forming means is formed by the ridge that spirals on the opposite surface of the chuck base, the centripetal force can be easily obtained without hindering each suction means and each fixing means. Forming means can be provided.

According to the seventh aspect of the present invention, the wafer can be easily fixed to the wafer seat of the chuck base by the holding claws.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1, a wafer holding device 10 is shown in a schematic perspective view. The wafer holding device 10 includes a chuck base 11 having a disk shape and a rotary shaft 12 that rotatably supports the chuck base 11, and the chuck base 11 and the rotary shaft 12 are positioned concentrically. . Below, let the extending direction of the rotating shaft 12 be an up-down direction. FIG. 2 is a front view of the wafer holding device 10 as viewed from above, but the auxiliary wing 22 described later is omitted. 3 is a cross-sectional view taken along the line I-I in FIG. 1. FIG. 4 is a cross-sectional view of the chuck base 11 for explaining the configuration of the rotary shaft 12 and a blowout hole 21 to be described later. 3 is a schematic perspective view partially showing the vicinity of a center O. FIG.

  The chuck base 11 has a wafer seat 13 and four holding claws 14.

  The wafer seat 13 has a ring shape composed of an annular ridge that rises over the entire circumference at the peripheral edge portion 11b of the upper surface 11a of the chuck base 11 (see FIG. 3), and the upper surface 13a is horizontal. It is considered to be a good surface.

  The four holding claws 14 are configured to be equal to each other. As shown in FIG. 2, when viewed from above, the four holding claws 14 are curved along the peripheral edge portion 11 b of the chuck base 11. The holding claws 14 are provided at positions that are perpendicular to each other and at equal intervals. As shown in FIG. 3, each holding claw 14 has a protruding portion 14a, an extending portion 14b, and a connecting portion 14c.

  The protruding portion 14a protrudes from the outer periphery of the peripheral edge portion 11b of the chuck base plate 11 toward the center side of the chuck base plate 11, and the lower side is an inclined surface 14d. The extending portion 14 b extends along the back surface of the chuck base plate 11, and the connecting portion 14 c extends in the vertical direction outside the peripheral edge portion 11 b of the chuck base plate 11. Each holding claw 14 is configured by connecting a projection 14a and an extending portion 14b by a connecting portion 14c. Although not shown, the holding pawl 14 is movable in the radial direction of the chuck base 11 by a drive mechanism.

  In the wafer holding device 10, when the four holding claws 14 come into contact with the peripheral edge 15 a of the wafer 15 placed on the upper surface 13 a of the wafer seat 13 of the chuck base 11, each holding claw 14 is moved in the radial direction. While holding the wafer 15, the holding claws 14 press the wafer 15 against the upper surface 13 a of the wafer seat 13 in the vertical direction, so that the wafer 15 can be held while being fixed to the wafer seat 13. At this time, the upper surface 11 a of the chuck base 11 becomes an opposing surface facing the wafer 15, and an opposing space S defined by the chuck base 11 (upper surface 11 a) and the wafer seat 13 is formed below the wafer 15. It is formed.

  In the wafer holding device 10 according to the present invention, in addition to the above-described configuration, the communication hole 20, the blowout hole 21, the auxiliary wing 22, and the claw position suction hole 23 are provided in the chuck base 11.

  In this embodiment, the communication holes 20 are provided at four locations on the upper surface 11a of the chuck base 11 as shown in FIG. Each communication hole 20 includes an open hole portion 20a, a communication hole portion 20b, and a shaft hole portion 20c. Each open hole portion 20a (each communication hole 20) has an equal interval from the holding claws 14 located in the vicinity of the peripheral edge portion 11b of the chuck base plate 11 and on both sides when viewed in the circumferential direction of the chuck base plate 11. It is provided in the position. Each open hole 20a is formed by drilling the chuck base 11 in the vertical direction from the upper surface 11a of the chuck base 11 (see FIG. 3).

  Each communication hole 20b is provided corresponding to each open hole 20a, and the chuck base 11 is formed in the radial direction so as to communicate each open hole 20a and the shaft hole 20c. Yes. In the present embodiment, each communication hole 20b is filled with a portion located closer to the peripheral edge 11b side of the chuck base 11 than each open hole 20a after the chuck base 11 is drilled in the radial direction. Is formed.

  The shaft hole portion 20 c has a cylindrical shape centered on the center O of the chuck base 11, extends in the vertical direction inside the rotating shaft 12, and is partitioned from the blow hole 21 while surrounding the blow hole 21. (See FIGS. 2, 3 and 4.) For this reason, each open hole 20a and each communication hole 20b are joined at the shaft hole 20c (see FIGS. 2 and 4), and the opposing space S is made outside through the common shaft hole 20c. It is communicated. The shaft hole portion 20c is connected to the suction device (vacuum device) P1 on the outside of the facing space S. Each communication hole 20 and the suction device P1 function as a suction mechanism capable of sucking air in the facing space S.

  The blowout hole 21 has a cylindrical shape centered on the center O of the chuck base 11 and extends in the vertical direction inside the rotation shaft 12 inside the shaft hole portion 20c of the communication hole 20 (FIG. 2). , See FIG. 3 and FIG. The configuration of the rotary shaft 12 is, for example, that the chuck base 11 is drilled to form a through hole equal to the outer diameter of the shaft hole portion 20c of the communication hole 20, and a cylindrical body having an inner diameter equal to the blowout hole 21 is formed in this through hole. Can be formed. The blowout hole 21 is connected to a supply device (compression device) P2 capable of spraying clean air from which dust and the like are removed. The blowout hole 21 and the supply device P2 function as a supply mechanism that can supply air to the facing space S.

  In the present embodiment, as shown in FIG. 1, the auxiliary wing 22 is provided such that a plurality of ridges 22 a protruding from the upper surface 11 a of the chuck base 11 draw a spiral toward the center O of the chuck base 11. Formed (radial and each spiraling). The cross section of each protrusion 22a has a rectangular shape in this embodiment (see FIG. 3). When the chuck base 11 is rotationally driven by the rotary shaft 12 (see arrow D in FIG. 1), the auxiliary wings 22 are centripetally forced toward the center O from the peripheral edge 11b of the chuck base 11 by the air in the facing space S (see FIG. 1). 3 (see arrow E in FIG. 3), that is, the center O of the chuck base 11 can be generated so that an air flow from the peripheral edge 11b of the chuck base 11 toward the center O can be generated. It is formed so as to draw a spiral and a spiral toward. For this reason, when the chuck base 11 is rotationally driven, the auxiliary wing 22 can suppress the air in the facing space S from moving toward the peripheral edge 11 b of the chuck base 11 due to the centrifugal force.

  The claw position suction holes 23 are provided at four locations corresponding to the holding claws 14 and have four claw position suction holes 23a. Each claw position suction hole 23 a has one end communicating with the gap G between each holding claw 14 and the peripheral edge 11 b of the chuck base 11, and the other end being a shaft hole of the communication hole 20 formed in the rotary shaft 12. It communicates with the portion 20c. Each claw position suction hole 23 and the suction device P1 function as a claw position suction mechanism capable of sucking air in the gap G. The claw position suction mechanism may have a configuration in which components other than the claw position suction holes 23a, that is, the shaft hole 20c and the suction device P1 are provided separately from the suction mechanism described above. The present invention is not limited to the examples.

  Further, although not shown in the drawings, the wafer holding apparatus 10 of the present embodiment is provided with detection means capable of detecting the rotation speed of the chuck base plate 11 when being rotated by the rotation shaft 12. This detection means is electrically connected to a control device (not shown) that controls the operation of the suction device P1 and the supply device P2. This control device adjusts the suction amount by the suction device P1 and the supply amount by the supply device P2 described above in consideration of the centrifugal force that changes according to the rotational speed of the chuck base plate 11, that is, according to the rotational speed. Is set to For this reason, in the wafer holding device 10, the amount of air sucked into the facing space S through the communication hole 20 and the amount of air supplied to the facing space S through the blowout hole 21 change according to the rotation speed of the chuck base 11. Is done.

  The wafer holding device 10 is used in a surface inspection device 16 as shown in FIG. In the surface inspection apparatus 16, the surface 15b of the wafer 15 is irradiated with laser light L from an oblique direction (see reference numeral I), and scattered light generated when foreign matter such as dust adheres to the irradiation position I of the surface 15b. Can be detected by a PMT (photomultiplier tube) 17 to detect foreign matter on the surface 15b of the wafer 15. At this time, the surface inspection apparatus 16 shifts the irradiation position I of the laser beam L on the surface 15b of the wafer 15 along the radial direction of the wafer 15 while rotating the wafer 15 at a high speed, so that the surface 15b of the wafer 15 is shifted. Can be inspected over the entire surface.

  In the wafer holding apparatus 10 according to the present embodiment, the following effects can be obtained.

  (1) The wafer 15 can be held by fixing the wafer 15 positioned on the upper surface 13a of the wafer seat 13 of the chuck base 11 to the wafer seat 13 with the four holding claws 14, and in this holding state. The wafer 15 can be rotated together with the chuck base 11 by the rotational drive of the rotary shaft 12. At this time, in the facing space S below the wafer 15, the centrifugal force acts on the air as the chuck base 11 rotates, so that the pressure near the peripheral edge 11 b is the highest and the pressure at the center O is the highest. Pressure deviations that can be reduced can occur. When the pressure of the peripheral edge portion 11b is increased in the facing space S, the gap between the wafer 15 and the chuck base 11 is located near the peripheral edge 15a of the wafer 15 at a location pressed against the wafer seat 13 by the inclined surface 14d of each holding claw 14. Is a predetermined one equal to the holding state, but at a place where the holding claw 14 is not provided, the distance from the chuck base 11 is larger than the predetermined one, and swells up and down when viewed in the circumferential direction. Wave-like deflection can occur. However, in the wafer holding device 10 of the present invention, the air in the facing space S is sucked by the suction device P1 through the communication hole 20 (see arrow A in FIG. 3). For this reason, it is possible to locally prevent the pressure at the position between the holding claws 14 from rising in the vicinity of the peripheral edge portion 11 b in the facing space S, and bending occurs in the vicinity of the peripheral edge 15 a of the wafer 15. This can be prevented.

  (2) The distance between the wafer 15 and the upper surface 11a of the chuck base plate 11 is maintained at the position of the center O due to the pressure deviation in which the pressure at the peripheral edge 11b is the highest and the pressure at the center O is the lowest in the facing space S. A bending deformation may occur that is smaller than a certain state, that is, the vicinity of the center O is recessed. However, at the center O of the chuck base 11, air is blown out to the facing space S by the supply device P <b> 2 through the blowing hole 21 (see arrow B in FIG. 3), so that the pressure near the center O of the facing space S is Can be prevented from decreasing. For this reason, in the facing space S, it is possible to locally prevent the pressure at the center O ′ of the wafer 15 from being lowered, and to prevent a bend such that the vicinity of the center O ′ of the wafer 15 is recessed.

  (3) Since the suction amount to the communication hole 20 and the supply amount from the blow hole 21 are adjusted according to the rotation speed of the chuck base plate 11, it is adapted to the pressure deviation due to the centrifugal force acting on the air in the facing space S. Thus, the pressure in the facing space S can be locally adjusted.

  (4) An auxiliary wing 22 is provided on the upper surface 11 a of the chuck base plate 11. When the chuck base plate 11 is rotationally driven by the rotary shaft 12, the air in the facing space S is chucked by the auxiliary wing 22. Since the centripetal force from the peripheral edge portion 11b of the base plate 11 toward the center O is applied, it is possible to reduce the pressure deviation such that the pressure at the peripheral edge portion 11b is the highest and the pressure at the center O is the lowest in the facing space S. it can. For this reason, even when the communication hole 20 and the blowout hole 21 are configured to pass through the inside of the rotary shaft 12 and the flow rate is limited as in this embodiment, the functions of the communication hole 20 and the blowout hole 21 are achieved. Since the auxiliary wings 22 can assist, it is possible to prevent the wafer 15 from being appropriately bent.

  (5) Even when the wafer 15 is rotated at high speed, that is, when the chuck base 11 is rotationally driven at high speed, it is possible to prevent the wafer 15 from being bent. If used, the deviation of the irradiation position and the focal position of the laser beam L due to the bending of the wafer 15 can be prevented, so that an accurate surface inspection can be performed.

  (6) Even when dust or the like is rolled up when each holding claw 14 comes into contact with the wafer 15, the gap G (each holding claw 14 and the peripheral portion 11 b of the chuck base 11 is connected to the claw position suction hole 23). ) Is sucked in, so that dust and the like that are wound up can be prevented from adhering to the surface 15b of the wafer 15.

  (7) In the facing space S, air is sucked from the communication hole 20, and clean air (clean air) is blown from the blowing hole 21. For this reason, in the facing space S, even if dust or the like is present, reflux that can be replaced with clean air is constantly occurring, and thus dust or the like adheres to the back surface 15c of the wafer 15. Can be prevented.

  Therefore, in the wafer holding apparatus 10 according to the present embodiment, the wafer 15 can be held without causing the wafer 15 to bend even if the chuck base 11 is rotationally driven to rotate the wafer 15.

  In the above-described embodiment, each holding claw 14 functions as a fixing unit that fixes the wafer 15 to the wafer seat 13 of the chuck base 11. Well, it is not limited to the embodiments described above.

  In the above-described embodiments, the wafer holding device 10 is used in the surface inspection device 16. For example, a photosensitive agent (photoresist) formed or applied on the surface of the wafer by irradiating light. Further, the present invention may be used for a semiconductor exposure apparatus that exposes and transfers a circuit pattern, a wafer transfer apparatus that transfers a circuit pattern while holding the wafer, and is not limited to the above-described embodiments.

  In the embodiment described above, as shown in FIG. 1, the auxiliary wing 22 is formed by a plurality of protrusions 22a provided in a radial and spiral manner. However, when the chuck base 11 is driven to rotate, The air in the facing space S can be prevented from moving toward the peripheral edge 11b side of the chuck base 11 due to the centrifugal force. That is, the air in the opposing space S moves from the peripheral edge 11b of the chuck base 11 to the center O. For example, as shown in FIG. 6, it may be formed by a single spiral (spiral) protrusion 22a 'as shown in FIG. 6, and is limited to the above-described embodiment. is not.

  In the above-described embodiment, each communication hole 20 is configured to merge at the shaft hole portion 20c provided inside the rotary shaft 12, but any configuration may be used as long as the opposing space S communicates with the outside. However, the present invention is not limited to the examples.

  In the above-described embodiment, each protrusion 22a forming the auxiliary wing 22 has a rectangular cross section (see FIG. 3). However, when the chuck base 11 is driven to rotate, the chuck base is exposed to the air in the facing space S. As long as it gives a centripetal force from the peripheral edge 11b of the board 11 toward the center O, for example, as shown in FIG. 7A, it may have a curved shape (22a ″). As shown in b), it may be an inclined shape (22a '') and is not limited to the above-described embodiment.

1 is a perspective view schematically showing a wafer holding device according to the present invention. It is a front view which shows the wafer holding apparatus which concerns on this invention, and has abbreviate | omitted and shown the centripetal force formation means. It is sectional drawing obtained along the II line | wire of FIG. It is a typical perspective view which shows partially the vicinity of the center of a chuck | zipper base for description of structures, such as a rotating shaft and a spray hole mentioned later. It is a front view which shows typically the surface inspection apparatus in which the wafer holding apparatus which concerns on this invention was used. It is a front view which shows the centripetal force formation means of the other example of the wafer holding apparatus which concerns on this invention. It is sectional drawing which partially expands and shows the centripetal force formation means of the other example of the wafer holding apparatus which concerns on this invention, (a) is an example curved, (b) It is an example inclined. It is a perspective view which shows the conventional wafer holding apparatus typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wafer holding device 11 Chuck base plate 11b Peripheral part 13 Wafer seat 14 Holding claw 15 (As a fixing means) Wafer 15a Peripheral edge 20 Communication hole 21 Outlet 22 Auxiliary blade 22a Projection P1 Suction means P2 Supply means S Opposite space

Claims (7)

A ring-shaped wafer seat is provided along the periphery of a disk-shaped chuck base that is rotatably supported, and the wafer is placed on the wafer by a plurality of fixing means. A wafer holding device capable of holding the wafer by being fixed to a seat,
Comprising detection means for detecting the rotational speed of the chuck base,
In the wafer seat, the fixing means are provided at intervals in the circumferential direction,
Between the respective fixing means, a plurality of communication holes for communicating the opposing space outside between the fixed said wafer to said wafer seat and said chuck base block is, a peripheral portion of the chuck base block Provided inward of the wafer seat as seen in the radial direction of the chuck base ,
Each communication hole is connected to a suction means for sucking air in the facing space ,
The suction means, the wafer holding device suction amount according to the rotational speed of the chuck base block is characterized Rukoto adjusted. Wherein each fixing means and said each communicating hole, the alternately arranged at equal intervals as viewed in the circumferential direction of the wafer, each communication hole, is equal position as viewed in the radial direction of the wafer Rukoto The wafer holding device according to claim 1. The chuck base is provided with a blowout hole that communicates the opposed space with the outside in the radial direction when viewed in the radial direction, and supplies air to the opposed space through the blowout hole. 3. The wafer holding apparatus according to claim 1, wherein means are connected . Said supply means, a wafer holding device according to claim 3, the supply amount in accordance with the rotational speed of said detected chuck base block by the detecting means, characterized in Rukoto adjusted. The said chuck base block, Rukoto have auxiliary blades for preventing the air of the counter space by the action of centrifugal force caused by the rotation of the chuck table board is toward the periphery of the chuck Taiban is provided The wafer holding apparatus according to claim 1, wherein: The auxiliary wing is formed by at least one protrusion provided on an opposing surface of the chuck base plate facing the wafer, and each protrusion has a spiral shape toward the rotation center of the chuck base plate. wafer holding apparatus according to claim 5, characterized in that it is. Each fixing means is a holding claw capable of coming into contact with a peripheral edge of the wafer, and each holding claw is provided on the chuck base so as to be movable in a radial direction of the chuck base, and each of the holding claws is provided on the wafer. wafer holding device according to any one of claims 1 to 6, characterized in Rukoto sandwiched with the wafer is pressed against the wafer seat by abutting the peripheral edge of the.

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