JP2005209728A - Wafer gripping apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer gripping apparatus that is not affected by the shape of a body to be gripped, is suitable for a semiconductor wafer carrying device having a fork whose breadth is narrower than the body to be gripped, and does not damage the body to be gripped even if the supply of power is stopped. <P>SOLUTION: The wafer gripping device for the body W to be gripped has a locking mechanism comprising a compression spring 14 that is arranged in the longitudinal direction in an enclosure 11, while one end is fixed to the bottom lid 13 of the enclosure 11, and the other end is connected to a gripping body 17; shape memory alloy springs 15A, 15B that are provided at the inner middle of the compression spring 14, while one end is fixed to a bottom lid 13 of the enclosure 11, and the other end is connected to the gripping body 17 via a spring fixing member 12, and force is applied in a direction for releasing the gripping body 17 against the compression spring 14; and nibs 20A, 20B for locking, shape memory alloy springs 21A, 21B for locking, and the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wafer gripping apparatus for gripping a thin plate-like target body such as a semiconductor wafer.

Conventionally, an elastic body that urges the gripping body in the opening direction or the closing direction is provided, the center of the gripping body is provided at the end of the elastic body, and the shape memory alloy is placed between the opposite ends of the gripping body. A wafer gripping device provided with a drive unit and provided with a holding unit for gripping a gripped body such as a semiconductor wafer at the tip of the gripping body is as shown in FIG. 6 (see, for example, Patent Document 1).
FIG. 6 is a front view of a conventional wafer holding apparatus.
In FIG. 6, one ends of elastic bodies 42 and 43 that extend above the base 41 are attached to both sides of the base 41. Grip bodies 44 and 45 are attached to the other ends of these elastic bodies 42 and 43 via central projections 44E and 45E, respectively. At one end of the gripping bodies 44 and 45, first holding portions 44A and 45A that hold the lower peripheral edge of the gripped body W, and second holding portions 44B and 44C that hold the peripheral flat surface of the gripping body W, 45B and 45C and movement allowance portions 44D and 44D for moving the object to be grasped W upward are provided. Between the other ends 44F and 45F of the grip bodies 44 and 45, a linear shape memory alloy 46 serving as a drive unit for opening and closing the grip bodies 44 and 45 is disposed. The shape memory alloy 46 memorizes its shape so as to generate a restoring force that shortens its length by heating. This shape memory alloy 46 is connected to a power source 48 through a switch 47. The elastic bodies 42 and 43 described above are given initial deflection for urging the grip bodies 44 and 45 in the closing direction. An operation of opening the gripping target W in the gripping state of the gripping target W indicated by a solid line will be described. When the shape memory alloy 46 is heated, the shape memory alloy 46 generates a recovery force that resists the deformation force of the elastic bodies 42 and 43, and draws the other one ends 44 </ b> F and 45 </ b> F of the grip bodies 44 and 45. As a result, the gripping bodies 44 and 45 are opened, and the gripped body W is opened. As a result, the object to be grasped W can be placed on a jig or the like.
Next, when the object to be grasped W is grasped, the shape memory alloy 6 is cooled contrary to the above-described operation. As a result, the recovery force of the shape memory alloy 6 is reduced, so that the gripping bodies 44 and 45 have a large pressing force on the gripped body W as shown by the one-dot chain line in FIG. The object to be grasped W is sandwiched in such a manner that the lower periphery of the object to be grasped W is held by the grasping bodies 44A and 45A.
Japanese Patent Publication No. 7-4787 (pages 5-9, FIG. 1)

In the conventional wafer gripping device, when the gripping body W is gripped or released horizontally by the gripping bodies 44 and 45, the gripping bodies 44 and 45 are larger than the lateral width of the gripping body W with respect to the gripping body W. Since it opens, there is a problem that the wafer gripping device interferes with the wafer cassette or FOUP when transported to a wafer cassette or FOUP having a narrower width than the diameter of the gripping body. Therefore, it is also applicable to a semiconductor wafer transfer device that can be transferred by using a fork with a narrower width than the diameter of the gripped body, while holding and releasing the gripped body without being affected by the shape of the gripped body. It has been desired to provide a wafer gripping device that can do this.
In addition, since the conventional wafer gripping apparatus opens the gripped body W while the shape memory alloy is energized, the grippers 44 and 45 are separated from the gripped body W after the gripped body W is opened. When the power supply is stopped due to a power failure or the like, the grip bodies 44 and 45 are closed. At this time, if the gripping body W is in the driving range of the gripping bodies 44 and 45, there is a problem that the gripping body W may fall from a jig or the like and be damaged.
The present invention has been made to solve the above problems, and can be applied to a semiconductor wafer transfer apparatus having a fork having a narrower width than the gripped body without being affected by the shape of the gripped body, An object of the present invention is to provide a wafer gripping device that does not damage a gripped object even when power supply is stopped.

In order to solve the above problem, the present invention is configured as follows.
The invention of claim 1 is a wafer gripping device for gripping the outer periphery of a gripped body such as a semiconductor wafer as a gripping target location by a gripping body, and a cylindrical housing having one end closed and the other end opened; An elastic body disposed so as to extend in the longitudinal direction of both ends in the housing, one end fixed to the bottom cover of the housing, and the other end connected to the gripping body; A coil-shaped shape memory alloy member having an end fixed to the bottom lid of the housing and the other end connected to the gripping body and applying force in a direction to open the gripping body against the elastic body; And a lock mechanism that locks the gripping body when the gripping body opens the gripped body and the gripping body is lowered to a predetermined position in the housing.
According to a second aspect of the present invention, in the wafer gripping apparatus according to the first aspect, a coiled compression spring is used for the elastic body, a shape memory alloy tension spring is used for the shape memory alloy member, and the shape memory is used. An alloy tension spring is provided at an inner middle portion of the compression spring.
The invention according to claim 3 is the wafer gripping apparatus according to claim 1, wherein the lock mechanism includes a pair of lock support members connected to the outside of the housing, and one end of the lock support member. And a leaf spring that is an elastic body with the other end connected to the locking claw, and a surface between the opposite side to which the locking claw of the leaf spring is attached and the locking support member And a coil-shaped shape memory alloy spring for locking that applies a force in a direction to open the locking claw against the gripping body against the leaf spring.
According to a fourth aspect of the present invention, in the wafer gripping apparatus according to the first aspect, the locking mechanism includes a pair of locking casings connected to the outside of the casing, and one end of the locking casing. A coiled compression spring for locking which is an elastic body with the other end connected to the locking claw, and an inner intermediate portion of the locking compression spring, and one end is the locking casing A coil-shaped shape memory alloy for a lock that is fixed to the bottom of the metal and has the other end connected to the lock claw and applies a force in a direction to open the lock claw against the grip body against the lock compression spring It consists of a spring.

According to the first aspect of the present invention, there is provided a wafer gripping device that can be used for a transfer device that is inserted into a wafer cassette or FOUP while the gripping body is mounted on a fork or the like with a fork whose width is narrower than the width of the gripping body. It is possible to provide a wafer gripping device that can be provided and does not damage the gripped object even when the supply of power is stopped.
According to the invention described in claim 2, the gripping mechanism can be miniaturized.
Moreover, according to invention of Claim 3, 4, a locking mechanism can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a front sectional view of a wafer gripping apparatus showing a first embodiment of the present invention, and shows a gripping state. FIG. 2 is a front sectional view showing the opened state of the wafer gripping apparatus of FIG. FIG. 5 is a conceptual diagram showing an example in which the wafer gripping device of the present invention is applied to a wafer transfer device in combination with a fork.
In FIG. 1, W is a body to be grasped, 11 is a housing, 12 is a spring fixing member, 13 is a bottom cover, 14 is a compression spring, one end of the compression spring 14 is connected to the spring fixing member 12, and the other end of the compression spring 14. The end is connected to the bottom lid 13. 15A, 15B are shape memory alloy springs for gripping, 16A, 16B, 16C, 16D and 16E are conductors, 17 are gripping bodies, 18A, 18B are locking support members, 19A, 19B are leaf springs, 20A, 20B are for locking The claws 21A and 21B are locking shape memory alloy springs.
In FIG. 5, W is the object to be gripped, F is a fork, P is a pin provided on the fork, and H is the wafer gripping apparatus of the present invention. The wafer gripping device H is mounted on the fork F, and the wafer gripping device H and the fork F constitute a wafer transfer device, and the object to be gripped W is positioned by the pin P at the tip of the fork F. Is used so as to be gripped or released by a wafer gripping device H provided at the rear end of the fork F.
The features of the present invention are as follows.
That is, in the wafer gripping device that grips the outer peripheral edge of the gripped body W as a gripping target location by the gripping body 17, the cylindrical casing 11 having one end closed and the other end opened, and both ends in the casing 11 And an elastic body having one end fixed to the bottom lid 13 of the housing and the other end connected to the gripping body 17 via the spring fixing member 12. A coil-shaped compression spring 14 and an inner intermediate portion of the compression spring 14, one end is fixed to the bottom cover 13 of the casing, and the other end is connected to the gripping body 17 via the spring fixing member 12. In addition, coil-shaped gripping shape memory alloy springs 15A and 15B that apply force in a direction to open the gripping body 17 against the compression spring 14 are provided.
In addition, the wafer gripping apparatus is provided with a lock mechanism that locks the gripping body 17 when the gripping body 17 releases the gripped body W and the gripping body 17 is lowered to a predetermined position in the housing 11. Yes.
Specifically, the locking mechanism includes a pair of locking support members 18A and 18B connected to the outside of the housing 11, one end fixed to the locking support members 18A and 18B, and the other end for locking. Between the plate springs 19A and 19B, which are elastic bodies connected to the claws 20A and 20B, and the opposite surface of the plate springs 19A and 19B to which the locking claws 20A and 20B are attached, and the lock support members 18A and 18B. Coil-shaped locking shape memory alloy springs 21A and 21B that are arranged and apply force in a direction to open the locking claws 20A and 20B against the gripping body 17 against the plate springs 19A and 19B that are elastic bodies. It is composed of
Note that the shape memory alloy springs 15A and 15B for gripping are set so that the recovery force of the compression spring 14 exceeds the recovery force of the shape memory alloy springs 15A and 15B for gripping when the temperature is below the transformation temperature. The ends of the pair of gripping shape memory alloy springs 15A and 15B on the one spring fixing member 12 side are electrically connected by a conductor 16A, and the gripping shape memory alloy spring 15A on the other bottom lid 13 side. , 15B are connected to conductors 16B and 16C, respectively, and connected to a shape memory alloy driving device (not shown).
Then, the shape memory alloy springs 21A and 21B for locking are set so that the recovery force of the leaf springs 19A and 19B exceeds the recovery force of the shape memory alloy springs 21A and 21B for lock when the temperature is lower than the transformation temperature. Conductors 16D and 16E are connected to both ends of the locking shape memory alloy springs 21A and 21B, respectively, and connected to a shape memory alloy driving device (not shown).

First, the operation of gripping the wafer will be described with reference to FIGS.
FIG. 2 shows a state where the wafer W is opened. In this state, when the shape memory alloy springs 21A and 21B for locking are energized from a shape memory alloy driving device (not shown) and the transformation temperature is exceeded, a recovery force acts on the shape memory alloy springs 21A and 21B for locking as shown in FIG. Then, the leaf springs 19 </ b> A and 19 </ b> B are pulled in a direction away from the housing 11. As a result, the locking claws 20 </ b> A and 20 </ b> B are separated from the gripping body 17, so that the gripping body 17 is extended by the recovery force of the compression spring 14 and grips the wafer W. After gripping the wafer W, when the energization of the locking shape memory alloy springs 21A and 21B is stopped and the transformation temperature falls below the transformation temperature, the recovery force of the leaf springs 19A and 19B reduces the contracting force of the locking shape memory alloy springs 21A and 21B. Therefore, the leaf springs 19A and 19B move in a direction approaching the casing 11, and the locking claws 20A and 20B return to the state shown in FIG.

Next, the operation of opening the wafer will be described with reference to FIGS.
When the shape memory alloy springs 21A and 21B for locking are energized from a shape memory alloy driving device (not shown) in the wafer holding state shown in FIG. 1 and the transformation temperature is exceeded, the shape memory alloy springs 21A and 21B for locking are shown in FIG. A recovery force acts on the plate springs 19A and 19B, and the leaf springs 19A and 19B are pulled away from the housing 11. Subsequently, when the shape memory alloy springs 15A and 15B for gripping are energized from a shape memory alloy driving device (not shown) and the transformation temperature is exceeded, a restoring force acts on the shape memory alloy springs 15A and 15B for gripping, and the compression spring 14 is moved. Since the wafer W is contracted, the wafer W is released from the gripping body 17. Subsequently, when the shape memory alloy springs 21A and 21B for locking are turned off and the transformation temperature falls below the transformation temperature, the recovery force of the leaf springs 19A and 19B exceeds the contraction force of the shape memory alloy springs 21A and 21B for locking. The springs 19A and 19B move in a direction approaching the housing 11, and the locking claws 20A and 20B return to the state shown in FIG.

  Therefore, since the first embodiment of the present invention constitutes a gripping mechanism that moves linearly by combining an elastic body and a shape memory alloy, a fork having a lateral width smaller than the width of the gripped body can be used as a fork on a wafer cassette or FOUP. It is possible to provide a wafer gripping device that can be used in a transfer device that inserts a gripped body while it is placed. Further, since the gripping body is configured to be locked when the wafer is released, it is possible to provide a wafer gripping apparatus that does not damage the gripped body even when the supply of power is stopped.

FIG. 3 is a front sectional view of the wafer gripping apparatus showing the second embodiment, showing a gripping state. 4 is a front sectional view showing the opened state of the wafer gripping apparatus of FIG. Note that the description of the same constituent elements in the second embodiment as those in the first embodiment will be omitted, and different points will be described.
In the figure, 22A and 22B are locking shape memory alloy springs, 23A and 23B are locking casings, and 24A and 24B are locking compression springs.
The second embodiment is different from the first embodiment as follows.
That is, the lock mechanism is basically different, the lock mechanism is a pair of lock housings 23A and 23B connected to the outside of the housing 11, and one end is fixed to the lock housings 23A and 23B, while the other The ends are provided at the inner intermediate portions of the coiled compression springs 24A and 24B and the compression springs 24A and 24B, which are elastic bodies connected to the locking claws 20A and 20B. The bottom ends of the casings 23A and 23B are fixed, the other ends are connected to the lock claws 20A and 20B, and the lock claws 20A and 20B for the grip body 17 are opened against the lock compression springs 24A and 24B). It consists of coil-shaped locking shape memory alloy springs 21A and 21B that apply a force in the direction.
When the lock shape memory alloy springs 22A and 22B are below the transformation temperature, the recovery force of the lock compression springs 24A and 24B is set to exceed the recovery force of the lock shape memory alloy springs 22A and 22B. . Conductors 16D and 16E are connected to both ends of the locking shape memory alloy springs 22A and 22B, respectively, and are connected to a shape memory alloy driving device (not shown).

First, the operation of gripping the wafer will be described with reference to FIGS.
FIG. 4 shows a state where the wafer W is opened. In this state, when the shape memory alloy springs 21A and 21B for locking are energized from a shape memory alloy driving device (not shown) and the transformation temperature is exceeded, a restoring force acts on the shape memory alloy springs 21A and 21B for locking as shown in FIG. Then, the compression springs 24A and 24B for locking contract. As a result, the locking claws 20 </ b> A and 20 </ b> B are separated from the gripping body 17, so that the gripping body 17 is extended by the recovery force of the compression spring 14 and grips the wafer W. After gripping the wafer W, when the energization to the lock shape memory alloy springs 21A and 21B is stopped and the transformation temperature falls below the transformation temperature, the recovery force of the lock compression springs 24A and 24B is contracted by the lock shape memory alloy springs 21A and 21B. Since the force is exceeded, the locking compression springs 24A and 24B expand, and the locking claws 20A and 20B return to the state shown in FIG.

Next, the operation of opening the wafer will be described with reference to FIGS.
When the shape memory alloy springs 21A and 21B for locking are energized from a shape memory alloy driving device (not shown) in the wafer gripping state shown in FIG. 3 and the transformation temperature is exceeded, the shape memory alloy springs 21A and 21B for locking are shown in FIG. A restoring force acts on the locking compression springs 24A and 24B. Subsequently, when the shape memory alloy springs 15A and 15B for gripping are energized from a shape memory alloy driving device (not shown) and the transformation temperature is exceeded, a restoring force acts on the shape memory alloy springs 15A and 15B for gripping, and the compression spring 14 is moved. Since the wafer W is contracted, the wafer W is released from the gripping body 17. Subsequently, when energization of the lock shape memory alloy springs 21A and 21B is stopped and the transformation temperature falls below, the recovery force of the lock compression springs 24A and 24B exceeds the contraction force of the lock shape memory alloy springs 21A and 21B. The locking compression springs 24A and 24B expand, and the locking claws 20A and 20B return to the state shown in FIG. 4 again to lock the gripping body 17.

  Therefore, the second embodiment of the present invention constitutes a gripping mechanism that moves linearly by combining an elastic body and a shape memory alloy. Therefore, a fork having a lateral width smaller than the width of the gripped body can be used as a fork on a wafer cassette or FOUP. It is possible to provide a wafer gripping device that can be used in a transfer device that inserts a gripped body while it is placed. Further, since the gripping body is configured to be locked when the wafer is released, it is possible to provide a wafer gripping apparatus that does not damage the gripped body even when the supply of power is stopped.

  By moving the elastic body and shape memory alloy in a linear motion, it is compact, generates less dust, and can perform a quiet gripping operation. Since it is not damaged, the present invention can be applied not only to wafer conveyance but also to applications such as conveyance of foods and chemicals that require a gripping operation in a clean environment.

1 is a front sectional view of a wafer gripping apparatus showing a first embodiment of the present invention and shows a gripping state. Front sectional view showing the wafer opening state of the wafer gripping apparatus of FIG. It is a front sectional view of a wafer gripping apparatus showing a second embodiment of the present invention, and represents a gripping state. FIG. 4 is a front sectional view showing an opened state of the wafer gripping apparatus of FIG. 3. It is the conceptual diagram showing the example which applied the wafer holding apparatus of this invention to the wafer conveyance apparatus together with the fork. Front view of a conventional wafer gripping device

Explanation of symbols

W Non-gripping body (wafer)
11 Housing 12 Spring fixing member 13 Bottom lid 14 Compression springs 15A, 15B Shape memory alloy springs 16A, 16B, 16C, 16D for gripping Conductor 17 Grasping body 18A, 18B Support members 19A, 19B for locking Leaf springs 20A, 20B For locking Claw 21A, 21B, 22A, 22B Locking shape memory alloy spring 23A, 23B Locking casing 24A, 24B Locking compression spring

Claims (4)

In a wafer gripping device that grips the outer peripheral edge of a gripped body W such as a semiconductor wafer as a gripping target location by a gripping body,
A cylindrical housing with one end closed and the other end open;
An elastic body that is disposed so as to extend in the longitudinal direction of both ends in the housing, one end is fixed to the bottom lid of the housing, and the other end is connected to the gripping body;
A coil-shaped shape memory alloy member in which one end is fixed to the bottom lid of the casing and the other end is connected to the gripping body and applies force in a direction to open the gripping body against the elastic body When,
A wafer gripping apparatus, comprising: a lock mechanism that locks the gripping body when the gripping body opens the gripped body and the front gripping body is lowered to a predetermined position in the housing.   A coil-shaped compression spring is used for the elastic body, a shape memory alloy tension spring is used for the shape memory alloy member, and the shape memory alloy tension spring is provided in an inner intermediate portion of the compression spring. Item 2. A wafer gripping apparatus according to Item 1. The locking mechanism includes a pair of locking support members connected to the outside of the housing;
A leaf spring serving as an elastic body having one end fixed to the locking support member and the other end connected to the locking claw;
The leaf spring is disposed between the opposite surface of the lock spring to which the locking claw is attached and the locking support member, and the force in the direction to open the locking claw against the gripper against the leaf spring. 2. A wafer gripping device according to claim 1, comprising a coil-shaped shape memory alloy spring for locking. The locking mechanism includes a pair of locking casings connected to the outside of the casing;
A coiled compression spring for locking which is an elastic body having one end fixed to the locking housing and the other end connected to the locking claw;
The lock compression spring is provided at an inner intermediate portion, one end is fixed to the bottom of the lock casing, the other end is connected to the lock claw, and is against the lock compression spring. 2. The wafer gripping apparatus according to claim 1, comprising a coil-shaped shape memory alloy spring for locking that applies a force in a direction to open the locking claw with respect to the gripping body.

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