JP2019197865A - Conveyance mechanism and conveyance method - Google Patents

Abstract

To provide a conveyance mechanism that is able to prevent positional deviation or damage of a wafer.SOLUTION: A conveyance mechanism by which a wafer is conveyed to a holding table having a holding surface smaller than a wafer and disposed on a base such that an outer peripheral part of the base is exposed, comprises: a conveyance arm; a conveyance head connected to the conveyance arm and holding the wafer; and moving means that moves the conveyance head. The conveyance head comprises an upper arm having a pressing part that presses an outer peripheral part of the wafer from an upper-surface side; a lower arm having a support part supporting the outer peripheral part of the wafer from a lower-surface side thereof, and composed so as to be movable in a direction parallel to the holding surface; and a pressure application mechanism that applies a pressure to the upper arm. The pressure application mechanism comprises: a spring member; the lock member disposed below the spring member and that is able to press the upper arm downward by elastic force of the spring member; and a guide pin disposed below the lock member and that pushes up the lock member toward the spring member when a lower end thereof is pressed upward.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transport mechanism for transporting a wafer and a transport method for transporting a wafer using the transport mechanism.

  When processing various types of wafers typified by semiconductor wafers, such as grinding, cutting and polishing, a processing apparatus having a holding table for holding the wafer is used, and the wafer is held on the holding table. Processed in the state. Such a processing apparatus is provided with a transport mechanism for transporting the wafer in order to place the wafer to be processed on the holding table or to remove the processed wafer from the holding table.

  As a transport mechanism, a mechanism that sucks and transports the surface of a wafer is widely used. Patent Document 1 discloses a transport mechanism that holds and sucks a wafer by bringing a suction pad connected to a suction source into contact with the surface of the wafer. However, when the suction pad is brought into contact with the surface of the wafer in this way, the surface of the wafer may be damaged, and for example, a device such as an IC (Integrated Circuit) formed on the surface of the wafer may be damaged.

  Therefore, in order to prevent damage to the wafer during conveyance, a conveyance mechanism configured to avoid contact with the wafer surface as much as possible has been proposed. Patent Document 2 discloses an edge clamp type transport mechanism that holds an outer peripheral portion of a wafer by three holding portions having recesses that engage with the outer peripheral portion of the wafer. Patent Document 3 discloses a Bernoulli-type transport mechanism that sucks and holds a wafer in a non-contact manner by ejecting air.

  In the edge clamp type or Bernoulli type transfer mechanism, the contact area between the transfer mechanism and the wafer at the time of transfer is significantly reduced as compared with a transfer mechanism that sucks the surface of the wafer with a suction pad. For this reason, it is possible to prevent the wafer from being damaged and improve the yield.

JP 2013-144323 A JP 2007-258450 A JP 2004-119784 A

  The above-mentioned edge clamp type transport mechanism moves the three holding portions provided with the concave portions along the radial direction of the wafer, and holds the wafer by engaging the outer peripheral portion of the wafer with the concave portions. At this time, if a strong pressure is applied from the concave portion to the outer peripheral portion of the wafer toward the radially inner side of the wafer, the wafer may be damaged. Therefore, when the outer peripheral portion of the wafer is engaged with the concave portion, the position of the holding portion is adjusted so that no pressure is applied to the wafer.

  However, if the wafer is held in a shallow region of the recess in order to avoid breakage of the wafer, the fixing of the wafer becomes insufficient. When the wafer is transported in this state, the wafer is shaken during the transport and a positional deviation occurs, and it becomes difficult to place the wafer at a desired position on the holding table. In addition, the wafer may be shocked and shocked during transportation to be damaged.

  Further, for example, when the wafer is placed on the holding table using the above-described edge clamp type transport mechanism, the lower end of the holding unit is first brought close to the holding table, and then the wafer is released from the holding unit and held. Land on the table. However, there is a problem that the position of the wafer is shifted at the time of landing, and it is difficult to accurately place the wafer at a desired position on the holding table.

  Further, the above-described problem of wafer misalignment and damage may occur even in a Bernoulli-type transport mechanism in which the wafer is likely to be insufficiently fixed because the wafer is sucked and held without contact.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a transport mechanism capable of preventing a positional deviation or damage of a wafer and a transport method for transporting a wafer using the transport mechanism.

  According to one aspect of the present invention, there is provided a transport mechanism for transporting a wafer to a holding table that is disposed on a base so that an outer peripheral portion of the base is exposed and has a holding surface smaller than the wafer. An arm, a transfer head connected to the transfer arm and holding the wafer, and a moving means for moving the transfer head, the transfer head pressing the outer peripheral portion of the wafer from the upper surface side A lower arm configured to be movable in a direction parallel to the holding surface, and a pressurizing force that applies pressure to the upper arm. The pressure mechanism is a spring member, a lock member disposed below the spring member, and capable of pressing the upper arm downward by the elastic force of the spring member, and the lock member Arranged on the underside And a guide pin that pushes up the lock member toward the spring member when the lower end is pressed upward, and the height from the lower end of the guide pin to the region of the support that supports the wafer is The transfer head holding the wafer by the pressing portion and the support portion is lowered, and the lower end portion of the guide pin is the outer periphery of the base. When pressed by the portion, the spring member is pressed and contracted by the lock member, and a transport mechanism is provided in which the pressing of the upper arm by the pressurizing mechanism is released.

  In the transfer mechanism, the wafer may contain lithium tantalate or lithium niobate.

  According to another aspect of the present invention, there is provided a transfer method for placing the wafer on the holding table using the transfer mechanism, wherein an air jetting step for jetting air from the holding surface, and the air After the ejection step, the transfer head holding the wafer is lowered to press the lower end portion of the guide pin against the outer peripheral portion of the base and release the upper arm by the pressurizing mechanism. After the pressure release step, after the pressure release step, the suction holding step of releasing the air blow from the holding surface and sucking and holding the wafer by the holding table, and the lower arm radially outward of the wafer And a lower arm retracting process for retracting to a lower arm.

  According to another aspect of the present invention, there is provided a transfer method for removing the wafer placed on the holding table from the holding table using the transfer mechanism, wherein the transfer head is lowered. By pressing the lower end portion of the guide pin against the outer peripheral portion of the base and releasing the pressure of the upper arm by the pressurizing mechanism, and after the pressurizing release step, by the holding table An air ejection step for releasing suction and holding air from the holding surface, a lower arm insertion step for inserting the lower arm below the outer peripheral portion of the wafer, and a lower arm insertion step The lower end portion of the guide pin is moved away from the outer peripheral portion of the base by raising the transfer head, and the upper arm is pressed by the pressurizing mechanism, and the wafer is held between the upper arm and the lower arm. You Conveying method comprising the pressurization step, it is provided.

  In the transfer method, the wafer may contain lithium tantalate or lithium niobate.

  A transfer mechanism according to an aspect of the present invention includes an upper arm and a lower arm that hold a wafer, and a pressurizing mechanism that includes a lock member that can press the upper arm by the elastic force of a spring member. Hold. The transport head operates in a mode in which the upper arm is pressed by the lock member and a mode in which the upper arm is not pressed by the lock member.

  By using this transport mechanism, the wafer can be transported while the outer peripheral portion of the wafer is reliably held from the upper surface side and the lower surface side by the upper arm and the lower arm, and misalignment or damage due to the shaking of the wafer can be prevented. In addition, the wafer can be placed on the holding table while being in contact with the upper arm, and positional displacement when the wafer is landed on the holding table due to friction between the wafer and the upper arm can be prevented.

FIG. 1A is a partially sectional front view showing the transport mechanism, and FIG. 1B is an enlarged view of the transport head. It is a top view which shows the positional relationship of an upper arm and a locking member. It is a figure which represents typically the structure of a conveyance head. It is an enlarged view of the conveyance head at the time of wafer conveyance. FIG. 6 is an enlarged view of the transport head in a state where the pressing by the lock member is released. FIG. 6A is a schematic diagram showing the state of the air ejection step, and FIGS. 6B and 6C are schematic diagrams showing the state of the pressure release step. FIG. 7A is a schematic view showing the state of the suction holding process, FIG. 7B is a schematic view showing the state of the lower arm retracting process, and FIG. 7C is a state where the transport head is raised. It is a schematic diagram shown. FIGS. 8A and 8B are schematic views showing the state of the pressurization releasing step, and FIG. 8C is a schematic view showing the state of the lower arm insertion step. FIG. 9A is a schematic diagram showing the state of the air ejection process, and FIGS. 9B and 9C are schematic diagrams showing the state of the pressurizing process.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1A is a partial cross-sectional front view showing a transport mechanism 2 according to this embodiment. The transport mechanism 2 transports a disk-shaped wafer 11 having an upper surface 11a and a lower surface 11b, for example.

  The material, shape, structure, size, etc. of the wafer 11 transported by the transport mechanism 2 are not limited. For example, a wafer made of a material such as a semiconductor (silicon, GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal or the like may be used as the wafer 11. The wafer 11 may be a wafer containing a brittle material such as lithium tantalate or lithium niobate.

  Further, a device such as an IC may be formed at the center of the wafer 11 on the upper surface 11a side. As will be described later, since the transport mechanism 2 holds the outer peripheral portion of the wafer 11 and transports the wafer 11, the transport mechanism 2 does not contact the central portion on the upper surface 11a side of the wafer 11, thereby avoiding damage to the device. .

  When performing various processes such as grinding, cutting, and polishing on the wafer 11, the wafer 11 is held by the holding table 6 provided on the base 4 of the processing apparatus. The upper surface of the holding table 6 is a circular holding surface 6 a that holds the wafer 11, and the holding surface 6 a is connected to a suction source (not shown) via a flow path (not shown) formed inside the holding table 6. It is connected. The wafer 11 is sucked and held by the holding table 6 by applying a negative pressure of a suction source to the holding surface 6 a with the wafer 11 placed on the holding table 6.

  Further, the holding surface 6 a is connected to an air supply source (not shown) through a flow path formed inside the holding table 6. By supplying air from the air supply source to the holding surface 6a via the flow path, the air can be ejected from the holding surface 6a toward the upper side of the holding table 6, and the wafer 11 can be floated on the holding table 6. .

  The shapes of the base 4 and the holding table 6 can be appropriately set according to the shape and type of the wafer 11. However, the upper surface of the base 4 is larger than the lower surface of the holding table 6, and the holding table 6 is arranged so that the upper surface of the outer peripheral portion 4 a of the base 4 is exposed outside the holding table 6.

  Further, the holding table 6 is configured to be able to hold an area excluding the outer peripheral portion of the wafer 11 on the holding surface 6a. Specifically, the holding surface 6a is smaller than the wafer 11, and is formed so that the outer peripheral portion of the wafer 11 does not contact the holding surface 6a when the wafer 11 is placed on the holding surface 6a. For example, the holding surface 6 a may be formed so that its diameter is smaller than the diameter of the wafer 11.

  When processing the wafer 11, the wafer 11 is carried in by the transfer device 2 and placed on the holding table 6. The processed wafer 11 is unloaded by the transfer device 2 and removed from the holding table 6.

  The transport mechanism 2 that transports the wafer 11 includes a base 8 and a plurality of transport heads 10 that are provided on the lower surface side of the base 8 and hold the wafer 11. For example, the base 8 is formed in a substantially rectangular shape or a circle in plan view, and four transport heads 10 are provided at equal intervals along the outer periphery of the base 8. FIG. 1A illustrates two of the four transport heads 10 that are provided at positions facing each other across a center line A penetrating the center of the base 8 in the vertical direction. . However, there is no restriction | limiting in the shape of the base 8, and if the number of the conveyance heads 10 is two or more, it can set arbitrarily.

  The central portion of the upper surface of the base 8 is attached to one end side of the transfer arm 12, and the other end side of the transfer arm 12 is connected to a moving means (not shown) that moves the transfer arm 12 in the horizontal direction and the vertical direction. ing. Therefore, the transport head 10 is connected to the transport arm 12 via the base 8, and the movement of the transport head 10 is controlled by the moving means.

  Four long holes 8 a penetrating up and down the base 8 are provided around the center line A at equiangular intervals on the outer periphery of the base 8. The longitudinal direction of each long hole 8a is, for example, along a straight line connecting the center of the base 8 and the position where each long hole 8a is provided. A columnar movable portion 14 constituting the transport head 10 is inserted into the long hole 8a. A support portion 16 configured to cover the movable portion 14 is attached to the lower surface side of the base 8.

  The long hole 8 a is formed so that the length in the longitudinal direction is larger than the width of the movable portion 14 and the length in the direction perpendicular to the longitudinal direction is substantially the same as the width of the movable portion 14. Therefore, the movable part 14 can move along the longitudinal direction of the long hole 8a inside the long hole 8a. Further, an air cylinder (not shown) disposed on the upper surface side of the base 8 is connected to the upper end side of the movable portion 14, for example.

  By the operation of the air cylinder, the movable portion 14 slides along the longitudinal direction of the long hole 8a. A holding part 14a is formed at the lower end of the movable part 14, and the movable part 14 surrounds and holds a part of the lower arm 20 in the holding part 14a.

  The lower arm 20 includes a held portion 20a held by a holding portion 14a, for example. The held portion 20a is disposed so that the longitudinal direction thereof extends along the direction from the holding portion 14a toward the center line A, and the lower surface 11b side of the wafer 11 is supported on the center line A side of the held portion 20a. The support part 20b is provided in such a manner that it protrudes from the support part 16 toward the center line A side.

  As described above, the lower arm 20 is held by the movable unit 14 connected to the air cylinder. Therefore, when the movable portion 14 is slid with the air cylinder, the lower arm 20 slides in the horizontal direction along the longitudinal direction of the long hole 8a.

  FIG. 1B is an enlarged view of the transport head 10. As shown in FIG. 1B, a step 20c suitable for supporting the wafer 11 is formed at the tip of the support portion 20b. The step 20c includes a bottom surface 20d substantially parallel to the horizontal direction and a side surface 20e substantially parallel to the vertical direction.

  An upper arm 18 is disposed immediately above the lower arm 20. The upper arm 18 includes a held portion 18 a that is disposed such that the longitudinal direction thereof extends along the direction from the connecting shaft 22 toward the center line A. The held portion 18a is provided with a through hole 18b extending in a horizontal direction perpendicular to the longitudinal direction of the upper arm 18, and the upper arm 18 is connected via a connecting shaft 22 inserted into the through hole 18b. The support portion 16 is mounted in such a manner that it can rotate around the shaft 22.

  Further, a pressing portion 18 c for pressing the upper surface 11 a side of the wafer 11 is provided on one end side (center line A side) of the held portion 18 a. As shown in FIG. 1B, a convex portion 18d that protrudes downward is provided at the lower end of the pressing portion 18c. The convex portion 18d is provided at a position corresponding to the step 20c of the lower arm 20, and the lower surface thereof is configured by, for example, a curved surface.

  The through hole 18b is provided on the other end side (the side opposite to the center line A) of the held portion 18a with respect to the position of the center of gravity of the upper arm 18. Therefore, when no external force is applied to the upper arm 18, the pressing portion 18c is lowered by the weight of the upper arm 18, and the upper surface 11a of the wafer 11 supported by the bottom surface 20d of the lower arm 20 is pressed by the pressing portion 18c. .

  When transporting the wafer 11, the wafer 11 is held by the upper arm 18 and the lower arm 20. Specifically, the bottom surface 20d of the support portion 20b supports the lower surface 11b of the wafer 11, and the convex portion 18d of the pressing portion 18c presses the upper surface 11a of the wafer 11 from above, so that the outer peripheral portion of the wafer 11 is the pressing portion. It is pinched by 18c and the support part 20b. The plurality of transfer heads 10 provided in the transfer mechanism 2 respectively hold the outer peripheral portion of the wafer 11, thereby holding the wafer 11 horizontally.

  In order to prevent the wafer 11 from being damaged when the pressing portion 18c and the support portion 20b are in contact with the wafer 11, the portions of the pressing portion 18c and the support portion 20b that are in contact with the wafer 11 are each made of a flexible material such as rubber or resin. It is preferable that the surface is formed by the material or is covered with the material.

  Further, the transport head 10 includes a pressurizing mechanism 24 that contacts the upper surface of the upper arm 18 and applies a downward pressure to the upper arm 18. The pressurizing mechanism 24 includes a lock member 26 that is movable in the vertical direction (vertical direction) with respect to the upper arm 18 by applying an external force, directly above the upper arm 18. The lock member 26 is arranged so that a part thereof overlaps with the upper arm 18.

  FIG. 2 is a plan view showing the positional relationship between the upper arm 18 and the lock member 26. The lock member 26 includes a rectangular parallelepiped first region 26 a that overlaps the pressing portion 18 c of the upper arm 18, and a rectangular parallelepiped second region 26 b that does not overlap the upper arm 18. Further, as shown in FIG. 1B, a convex portion 26c protruding toward the upper arm 18 is formed at the lower end of the first region 26a. When the lock member 26 moves downward with respect to the upper arm 18, the convex portion 26 c comes into contact with the upper surface of the upper arm 18.

  On the upper side of the lock member 26, a spring member 28 constituted by a coil spring or the like wound around a rod-shaped rod member is provided. One end side of the rod member is inserted into the base 8 so as to be movable in the vertical direction, and the other end side is connected to the upper surface of the second region 26 b of the lock member 26. The spring member 28 is held between the base 8 and the lock member 26 in a state of being contracted from the natural length. When the rod member slides up and down, the spring member 28 expands and contracts, and the lock member 26 moves up and down with respect to the upper arm 18.

  Specifically, when an external force is applied to the lock member 26 toward the upper side, the rod member is inserted into the base 8 and the spring member 28 is contracted, the lock member 26 is moved upward, and the convex portion 26c is moved. Move away from the upper surface of the upper arm 18. When the external force applied to the lock member 26 is released, the spring member 28 extends and the lock member 26 moves downward, and the convex portion 26 c presses the upper surface of the upper arm 18.

  The spring member 28 is not limited to a coil spring, and can be configured by an arbitrary elastic body having one end connected to the base 8 and the other end connected to the upper surface of the second region 26b of the lock member 26.

  A rod-shaped guide pin 30 connected to the lower surface of the second region 26 b of the lock member 26 is provided below the lock member 26. The guide pin 30 is disposed so as to protrude from the lower surface of the second region 26 b of the lock member 26 to the lower side of the support portion 16, and the lower end portion of the guide pin 30 has a base 4 that supports the holding table 6. A contact portion 30a that can come into contact with the outer peripheral portion 4a is formed.

As shown in FIG. 1A, the guide pin 30 is positioned at a position where the contact portion 30a overlaps the outer peripheral portion 4a of the base 4 when the wafer 11 held by the transfer mechanism 2 is positioned on the holding table 6. Be placed. The length of the guide pin 30 is such that the height H ₁ from the lower end of the guide pin 30 to the region of the support portion 20 b that supports the wafer 11, that is, the bottom surface 20 d (see FIG. 1B), It is set to be larger than the height H ₂ from the upper surface of the outer peripheral portion 4 a to the holding surface 6 a of the holding table 6.

  When the transport mechanism 12 is moved down with the transport mechanism 2 positioned so that the contact portion 30 a of the guide pin 30 overlaps the outer peripheral portion 4 a of the base 4, the transport mechanism 2 comes close to the holding table 6. The part 30 a contacts the outer peripheral part 4 a of the base 4. When the transport arm 12 is further lowered from this state, the contact portion 30a is pressed upward by the outer peripheral portion 4a of the base 4, and the guide pin 30 pushes the lock member 26 upward. As a result, the spring member 28 contracts, the lock member 26 moves upward with respect to the upper arm 18, and the convex portion 26 c of the lock member 26 moves away from the upper arm 18.

  On the other hand, when the transport arm 12 is raised from the state in which the contact portion 30a is pressed by the outer peripheral portion 4a of the base 4, the contact portion 30a of the guide pin 30 is separated from the outer peripheral portion 4a of the base 4, and the spring member 28 is moved. The locking member 26 extends and moves downward relative to the upper arm 18. Thereby, the convex portion 26 c of the lock member 26 and the upper arm 18 come into contact with each other, and the upper arm 18 is pressed toward the lower arm 20 by the elastic force of the spring member 28.

  FIG. 3 is a diagram schematically illustrating the structure of the transport head 10. All of the upper arm 18, the lower arm 20, and the pressurizing mechanism 24 included in the transport head 10 move as the transport arm 12 moves.

  The upper arm 18 is rotatable around the connecting shaft 22 in the direction indicated by the arrow B, and includes a pressing portion 18c on one end side and a contact portion 18e on the other end side. Further, the conveyance head 10 is provided with a rotation suppressing portion 32 fixed to the support portion 16 (see FIG. 1). When the upper arm 18 rotates more than a certain amount in the counterclockwise direction in FIG. 3, the contact portion 18 e comes into contact with the rotation suppressing portion 32, thereby preventing the upper arm 18 from rotating. Thereby, it is possible to prevent an excessive pressure from being applied to the wafer 11 held between the pressing portion 18c and the support portion 20b.

  The lower arm 20 includes a support portion 20b on one end side, and the other end side of the lower arm 20 is connected to an air cylinder 34 via a movable portion 14 (see FIG. 1). The air cylinder 34 includes a piston rod, and the lower arm 20 moves in a direction substantially parallel to the holding surface 6a of the holding table 6 (direction indicated by arrow C) by the reciprocating motion of the piston rod.

  The pressurizing mechanism 24 includes a lock member 26, a spring member 28, and a guide pin 30. The lock member 26 includes a convex portion 26 c that presses the upper arm 18, and the guide pin 30 is an outer peripheral portion of the base 4. The contact part 30a which contacts 4a is provided. The lock member 26 and the guide pin 30 can move in the vertical direction (the direction indicated by the arrow D) with respect to the upper arm 18 by contraction of the spring member 28.

  By moving the transfer arm 12 while the wafer 11 is held by the transfer head 10, the wafer 11 can be transferred to a desired place. Hereinafter, details of the operation of the transport head 10 when the wafer 11 is transported and placed on the holding table 6 will be described.

  FIG. 4 is an enlarged view of the transfer head 10 during wafer transfer. When transporting the wafer 11, the lower surface 11b of the wafer 11 is supported by the bottom surface 20d of the support portion 20b, and the upper surface 11a of the wafer 11 is pressed from above by the convex portion 18d of the pressing portion 18c. Thereby, the outer peripheral part of the wafer 11 is clamped by the pressing part 18 c and the support part 20 b, and the wafer 11 is held by the transport head 10.

  The spring member 28 is held between the base 8 and the lock member 26 in a state of being contracted from the natural length, and the elastic force of the spring member 28 is applied to the lock member 26. Therefore, the upper arm 18 is pressed downward by the lock member 26, and the upper surface 11a side of the wafer 11 is pressed by the convex portion 18d of the pressing portion 18c.

  At this time, a pressure derived from the weight of the upper arm 18 is applied to the upper surface 11 a side of the wafer 11, and a pressure derived from the elastic force of the spring member 28 is applied via the lock member 26. The part is securely locked between the upper arm 18 and the lower arm 20. For this reason, it is possible to prevent the wafer 11 from being shaken at the time of conveyance and causing the positional deviation or breakage of the wafer 11. In particular, when the wafer 11 is made of a brittle material such as lithium tantalate or lithium niobate, it is beneficial to suppress the impact caused by the shaking of the wafer 11.

  In addition, as shown in FIG. 4, the operation modes of the transport head 10 in which the pressure derived from the weight of the upper arm 18 and the pressure derived from the elastic force of the spring member 28 are applied to the upper surface 11a of the wafer 11 are as follows. Also referred to as “spring pressure mode”.

  Then, when the transfer arm 12 is moved and the wafer 11 held by the transfer head 10 is transferred above the holding table 6, the contact portion 30 a of the guide pin 30 is connected to the outer peripheral portion 4 a of the base 4 as shown in FIG. 4. Positioned to overlap. By lowering the transfer head 10 in this state, the wafer 11 is placed on the holding table 6.

Specifically, first, air is supplied from the air supply source (not shown) to the holding surface 6a of the holding table 6 so that air is ejected upward from the holding surface 6a and the transfer arm 12 is lowered. The wafer 11 is brought close to the holding table 6. Here, the height H ₁ from the lower end of the guide pin 30 to the region of the support portion 20 b that supports the wafer 11, that is, the bottom surface 20 d is from the upper surface of the outer peripheral portion 4 a of the base 4 to the holding surface 6 a of the holding table 6. Since the height is greater than H ₂ , the contact portion 30 a contacts the outer peripheral portion 4 a of the base 4 before the wafer 11 reaches the holding surface 6 a of the holding table 6.

  When the transport arm 12 is further lowered, the contact portion 30a is pressed by the outer peripheral portion 4a of the base 4, and the guide pin 30 is pushed upward. As a result, an upward pressure is applied to the lock member 26, the spring member 28 contracts, the lock member 26 moves upward with respect to the upper arm 18, and the convex portion 26 c moves away from the upper arm 18. Thereby, the pressing of the upper arm 18 by the lock member 26 is released. FIG. 5 is an enlarged view of the transport head 10 in a state where the pressing by the lock member 26 is released.

  When the convex portion 26 c is separated from the upper arm 18, only the pressure derived from the weight of the upper arm 18 is applied to the upper surface 11 a side of the wafer 11. That is, a lower pressure is applied to the upper surface 11a side of the wafer 11 than when the wafer 11 is transported (see FIG. 4). As shown in FIG. 5, the operation mode of the transport head in which only the pressure derived from the weight of the upper arm 18 is applied to the upper surface 11a of the wafer 11 is also referred to as “self-weight pressurizing mode”.

  When the wafer 11 approaches the holding table 6 in the self-weighting pressure mode, the wafer 11 floats away from the bottom surface 20d of the support portion 20b by the air blown from the holding surface 6a, and the support of the wafer 11 by the support portion 20b is released. It becomes a state. Since the upper arm 18 is rotatable around the connecting shaft 22, when the wafer 11 is disposed in the vicinity of the holding surface 6 a that blows out air, the wafer 11 floats and the pressing portion 18 c side of the upper arm 18 is located. The upper arm 18 rotates so that the pressing portion 18c moves upward.

  Thereafter, the ejection of air from the holding surface 6a is stopped, and the negative pressure of a suction source (not shown) is applied to the holding surface 6a, whereby the wafer 11 is sucked and held by the holding surface 6a. At this time, by gradually weakening the jet of air, the impact when the wafer 11 lands on the holding table 6 can be reduced.

  As described above, in the transport mechanism 2 according to the present embodiment, when the wafer 11 approaches the holding table 6 and the guide pins 30 come into contact with the base 4, the operation of the transport head 10 changes from the spring pressure mode to the self-weight pressure mode. Automatically switches to. Thereby, the pressure of the wafer 11 by the upper arm 18 is relaxed, and the impact when the wafer 11 comes into contact with the holding table 6 can be reduced.

  Further, since the upper surface 11 a side of the wafer 11 is in contact with the convex portion 18 d of the upper arm 18 when the wafer 11 is landed, the horizontal movement of the wafer 11 is limited by the friction between the wafer 11 and the upper arm 18. The Therefore, it is possible to prevent the wafer 11 from being displaced when the wafer 11 is placed on the holding table 6.

  Next, a specific example of a method for transporting the wafer 11 using the transport mechanism 2 according to the present embodiment will be described. Hereinafter, a wafer placing process for placing the wafer 11 on the holding table 6 and a wafer removing process for removing the wafer 11 placed on the holding table 6 from the holding table 6 will be described. 6 and 7 are diagrams schematically showing the state of the wafer placing step, and FIGS. 8 and 9 are views schematically showing the state of the wafer removing step.

  6 to 9 schematically show the wafer 11, the holding table 6, the pressing portion 18c of the upper arm 18, the support portion 20b of the lower arm 20, and the convex portion 26c of the lock member 26 for convenience of explanation of the transfer method. Is shown. The description of FIGS. 1 to 5 can be referred to for details of the configuration and functions of the transport mechanism 2 not described below.

<Wafer placement process>
First, air is supplied from the air supply source to the holding surface 6a of the holding table 6, and the air is ejected from the holding surface 6a (air ejection process). FIG. 6A is a schematic diagram showing the state of the air ejection process.

  Thereafter, the wafer 11 held between the pressing portion 18c of the upper arm 18 and the support portion 20b of the lower arm 20 is disposed above the holding table 6, and then the transfer head 10 is lowered toward the holding table 6 to The arm 18, the lower arm 20, and the lock member 26 are brought close to the holding table 6. As a result, as shown in FIG. 5, the contact portion 30a of the guide pin 30 is pressed against the outer peripheral portion 4a of the base 4, the spring member 28 is contracted, and the pressing of the upper arm 18 by the lock member 26 is released (given) Pressure release step).

  FIG. 6B and FIG. 6C are schematic views showing the state of the pressurization release process. The operation of the transport head 10 is switched from the spring pressure mode (FIG. 6B) to the self-weight pressure mode (FIG. 6C) by the pressure release process. When the wafer 11 approaches the holding surface 6a of the holding table 6 in the self-weighting pressure mode, the wafer 11 is floated by the air ejected from the holding surface 6a and is in contact with only the pressing portion 18c.

  Next, the ejection of air from the holding surface 6a is released, and the negative pressure of the suction source is applied to the holding surface 6a. Thereby, the wafer 11 is sucked and held by the holding table 6 (suction holding process). FIG. 7A is a schematic diagram showing a state of the suction holding process.

  During the suction holding process, the upper surface 11a side of the wafer 11 is in contact with the pressing portion 18c of the upper arm 18, and the horizontal movement of the wafer 11 is limited by the friction between the wafer 11 and the pressing portion 18c. The Therefore, positional deviation of the wafer 11 when the wafer 11 is landed on the holding table 6 is prevented.

  Thereafter, the air cylinder 34 (see FIG. 3) is operated to retract the lower arm 20 to the radially outer side of the wafer 11 (lower arm retracting step). FIG. 7B is a schematic diagram showing the state of the lower arm retracting step. Then, the transport head 10 is lifted away from the holding table 6 with the lower arm 20 retracted. Since the lower arm 20 is retracted outside the wafer 11 by the lower arm retracting process, the lower arm 20 does not contact the wafer 11 even when the transfer head 10 is raised.

  FIG. 7C is a schematic diagram illustrating a state where the transport head 10 is raised. When the transport head 10 is raised, the guide pin 30 is separated from the base 4 (see FIG. 4), and the operation of the transport head 10 is switched from the self-weight pressurizing mode to the spring pressurizing mode. Although the upper arm 18 rotates in the direction in which the pressing portion 18c is lowered by the raising of the transport head 10, the range of rotation of the upper arm 18 is limited by the rotation suppression unit 32 (see FIG. 3).

  Through the above process, the wafer 11 is sucked and held by the holding table 6. Thereafter, desired processing is performed on the wafer 11.

<Wafer removal process>
After processing the wafer 11, the processed wafer 11 is removed from the holding table 6. First, the transfer head 10 is lowered from the state in which the transfer head 10 is disposed above the holding table 6 on which the wafer 11 is sucked and held, and the upper arm 18, the lower arm 20, and the lock member 26 are brought closer to the holding table 6. As a result, as shown in FIG. 5, the contact portion 30a of the guide pin 30 is pressed against the outer peripheral portion 4a of the base 4, the spring member 28 is contracted, and the pressing of the upper arm 18 by the lock member 26 is released (given) Pressure release step).

  FIG. 8A and FIG. 8B are schematic views showing the state of the pressurization release process. By the pressurization release process, the operation of the transport head 10 is switched from the spring pressurization mode (FIG. 8A) to the self-weight pressurization mode (FIG. 8B). Then, the transfer head 10 is stopped in a state where the pressing portion 18 c of the upper arm 18 approaches or contacts the upper surface 11 a of the wafer 11.

  Next, the air cylinder 34 (see FIG. 3) is operated, and the support portion 20b of the lower arm 20 is inserted below the outer peripheral portion of the wafer 11 (lower arm insertion step). FIG. 8C is a schematic diagram showing the state of the lower arm insertion step. By the lower arm insertion step, the outer peripheral portion of the wafer 11 is disposed between the pressing portion 18c and the support portion 20b.

  In the lower arm insertion step, it is preferable to control the horizontal position of the lower arm 20 so that the support portion 20 b does not contact the side surface of the wafer 11. Thereby, it is possible to prevent the wafer 11 from being applied with a pressure toward the inside in the radial direction, and to avoid damage to the wafer 11.

  In this state, the suction holding of the wafer 11 by the holding table 6 is released, and air is jetted upward from the holding surface 6a of the holding table 6 (air jetting process). FIG. 9A is a schematic diagram showing the state of the air ejection process. The wafer 11 floats from the holding table 6 by the air ejection process and comes into contact with only the pressing portion 18c. In addition, you may implement a lower arm insertion process after an air ejection process.

  Thereafter, the transport head 10 is lifted away from the holding table 6. As a result, the lower arm 20 rises and the support portion 20 b comes into contact with the lower surface 11 b side of the wafer 11. Further, the guide pins 30 are separated from the base 4 (see FIG. 4), the operation of the transfer head 10 is switched from the self-weight pressurization mode to the spring pressurization mode, and the wafer 11 is held by the upper arm 18 and the lower arm 20. (Pressurizing step).

  FIG. 9B and FIG. 9C are schematic diagrams showing the pressurization process. By the pressurizing step, the operation of the transport head 10 is switched from the self-weight pressurizing mode (FIG. 9B) to the spring pressurizing mode (FIG. 9C). The wafer 11 is sandwiched between the pressing portion 18c and the support portion 20b. Through the above process, the processed wafer 11 is removed from the holding table 6.

  As described above, the transport mechanism 2 according to the present embodiment includes the upper arm 18 and the lower arm 20 that sandwich the wafer 11 and the lock member 26 that presses the upper arm 18 toward the wafer 11 by the elastic force of the spring member 28. The wafer 11 is held by the transfer head 10 having the pressurizing mechanism 24 provided. Further, the transport head 10 operates in a mode in which the upper arm 18 is pressed by the locking member 26 and a mode in which the pressing of the upper arm 18 by the locking member 26 is released.

  By using the transfer mechanism 2 described above, the upper arm 18 and the lower arm 20 can reliably hold the outer peripheral portion of the wafer 11 from the upper surface 11a side and the lower surface 11b side, and the wafer 11 can be transferred, and the wafer 11 can be prevented from shaking. . Further, the wafer 11 can be placed on the holding table 6 while being in contact with the upper arm 18, and positional displacement when the wafer 11 is landed on the holding table 6 due to friction between the wafer 11 and the upper arm 18 can be prevented.

  When the wafer 11 is transferred onto the holding table 6, first, the wafer 11 needs to be taken out from a cassette or the like in which the wafer 11 is accommodated, and the wafer 11 needs to be held by the transfer mechanism 2. The holding of the wafer 11 can be performed by, for example, the same operation as the above-described wafer removal process.

  Specifically, first, the lower surface 11b side of the wafer 11 is supported using a robot arm or the like, and the wafer 11 is taken out from the cassette. Then, the wafer 11 is temporarily placed on a temporary placement table having the same shape and dimensions as the support table 6 described above. The temporary placement table is provided on a temporary placement base that has the same shape and dimensions as the base 4 described above.

  Then, the transport mechanism 2 is positioned above the temporary table on which the wafer 11 is placed, and the transport mechanism 2 is operated in the same manner as the wafer removal process (see FIGS. 8 and 9). Thereby, the wafer 11 is held by the transfer head 10. In this way, the wafer 11 held by the transfer head 10 is placed on the support table 6 through the wafer placing process.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

2 transport mechanism 4 base 4a outer peripheral part 6 holding table 6a holding surface 8 base 8a long hole 10 transport head 12 transport arm 14 movable part 14a holding part 16 support part 18 upper arm 18a held part 18b through hole 18c pressing part 18d Convex part 18e Contact part 20 Lower arm 20a Holding part 20b Support part 20c Step 20d Bottom face 20e Side face 22 Connecting shaft 24 Pressurizing mechanism 26 Lock member 26a First area 26b Second area 26c Convex part 28 Spring member 30 Guide pin 30a Contact Part 32 Rotation suppression part 34 Air cylinder 11 Wafer 11a Upper surface 11b Lower surface

Claims (5)

A transport mechanism that transports a wafer to a holding table that is arranged on the base so that the outer periphery of the base is exposed and has a holding surface smaller than the wafer,
A transfer arm;
A transfer head connected to the transfer arm and holding the wafer;
Moving means for moving the transport head,
The transport head is
An upper arm including a pressing portion that presses the outer peripheral portion of the wafer from the upper surface side;
A lower arm configured to support the outer peripheral portion of the wafer from the lower surface side and configured to be movable in a direction parallel to the holding surface;
A pressurizing mechanism for applying pressure to the upper arm,
The pressurizing mechanism is
A spring member;
A lock member disposed on the lower side of the spring member and capable of pressing the upper arm downward by the elastic force of the spring member;
A guide pin that is disposed on the lower side of the lock member and pushes up the lock member toward the spring member when the lower end is pressed upward;
The height from the lower end of the guide pin to the region of the support that supports the wafer is greater than the height from the upper surface of the outer peripheral portion of the base to the holding surface,
When the transfer head holding the wafer is lowered by the pressing portion and the support portion and the lower end portion of the guide pin is pressed by the outer peripheral portion of the base, the spring member is pressed by the lock member. The transport mechanism is characterized in that the upper arm is pressed by the pressurizing mechanism.   The transport mechanism according to claim 1, wherein the wafer contains lithium tantalate or lithium niobate. A transfer method for placing the wafer on the holding table using the transfer mechanism according to claim 1,
An air ejection step for ejecting air from the holding surface;
After the air ejection step, the transfer head holding the wafer is lowered to press the lower end of the guide pin against the outer periphery of the base, and the pressing of the upper arm by the pressurizing mechanism is released. A pressurizing release process,
After the pressurizing release step, a suction holding step of releasing the ejection of air from the holding surface and sucking and holding the wafer by the holding table;
A lower arm retracting step for retracting the lower arm to the outside in the radial direction of the wafer. A transfer method for removing the wafer placed on the holding table from the holding table using the transfer mechanism according to claim 1,
A pressurization releasing step of pressing the lower end of the guide pin against the outer peripheral portion of the base by lowering the transport head, and releasing the pressing of the upper arm by the pressurizing mechanism;
After the pressurizing release step, an air ejection step for releasing the suction and holding of the wafer by the holding table and ejecting air from the holding surface;
A lower arm insertion step of inserting the lower arm below the outer peripheral portion of the wafer;
After the lower arm insertion step, by raising the transport head, the lower end portion of the guide pin is separated from the outer peripheral portion of the base, the upper arm is pressed by the pressurizing mechanism, and the wafer is And a pressurizing step of clamping by the arm and the lower arm.   5. The transfer method according to claim 3, wherein the wafer contains lithium tantalate or lithium niobate.