JP2009265256A - Holding device for thin plate, holding system for photomask having the device, and conveying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holding device for a thin plate, a holding system for a photomask which has the device, and a conveying method such that when the thin plate like the photomask is held, the displacement of the thin plate to be held can be absorbed without applying pressing force larger than constant pressure to the thin plate to be held. <P>SOLUTION: In the holding device 16 for the thin plate which has a pair of thin plate holding portions 28, an abutting portion has a base and an abutting body which engages the base while it can move relatively in a moving direction by a driving portion, and a first biasing means of biasing the abutting body in a direction wherein the interval is narrowed down is provided between the abutting body and the base; and the base is provided with a lock portion and then when the thin plate is held, one or both of the pair of thin plate holding portions 28 has/have a clearance generated between the abutting body and lock portion to form a displacement absorbing means and a pressing force limiting means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a thin plate holding device, a photomask holding system including the device, and a transport method, and more particularly, to prevent a thin plate to be held while preventing a pressing force above a certain level from acting on the thin plate to be held. The present invention relates to a thin plate holding device capable of absorbing misalignment, a photomask holding system having the device, and a transfer method.

2. Description of the Related Art Conventionally, a mechanism for holding an object in a form that is clamped by applying a pressing force has been adopted.
For example, Patent Document 1 discloses a holding device that holds opposite end faces to hold a thin plate such as a photomask.

The holding device is a thin plate holding device having a pair of thin plate holding portions, and each thin plate holding portion has a contact portion that comes into contact with a side surface of the thin plate and a drive unit that moves the contact portion. The abutting portion is provided with an O-ring that is an elastic member that abuts the thin plate to be held, and the drive portion narrows the interval between the corresponding contact portions of the pair of thin plate holding portions along the plane direction of the thin plate. Thus, the thin plate is held via the O-ring.

According to such a conventional holding device, when the thin plate is held, the amount of foreign matter generated from the contact portion with the thin plate is reduced, and the O-ring as the shock absorbing member attached to the contact portion is easily replaced. Is possible.
However, such a conventional holding device has the following technical problems.

First, when holding a thin plate, it is difficult to absorb the positional deviation of the thin plate to be held, and as a result, a sudden movement or impact acts on the thin plate during holding, thereby adversely affecting the thin plate. Is a point.
More specifically, when the thin plate is a photomask, the photomask is stored in a cassette composed of a cover and a base, and is transported together with the cassette. This is indispensable from the viewpoint of preventing contamination due to foreign matter adhering to the mask, particularly in the case of a next generation EUV mask that cannot use a pellicle. At this time, when the photomask is taken out from the cassette for processing the photomask, the clearance between the lower surface of the stored mask and the upper surface of the base is very small so that air does not enter the cassette storing the mask as much as possible. Therefore, for example, it is difficult to support the lower surface of the mask by a conventional transport mechanism that inserts a fork-shaped support portion between the clearances. Therefore, in order to support and transport the mask using the conventional transport mechanism, the clearance is expanded by holding the mask from the side once using another holding device and moving the base downward, for example. A fork-like support portion must be inserted into the conventional transfer mechanism.

However, due to the vertical and / or horizontal misalignment of the photomask, a sudden movement or impact may act on the thin plate during such delivery.

Secondly, when holding the thin plate from the side, the pressing force acting on the end surface of the thin plate inevitably increases according to the amount of movement of the thin plate holding portion regardless of the displacement of the thin plate, so the pressing force is excessive. Thus, sudden movements and impacts act on the thin plate, thereby adversely affecting the thin plate and possibly damaging the thin plate.
As described above, there is a strong demand to absorb the displacement of the thin plate to be held and to prevent the pressing force exceeding a certain level from acting on the thin plate to be held. If the pressure limiting mechanism is realized by a separate mechanism, it is not practical in view of the limited space around the photomask.
JP 2006-108155 A

In view of the above technical problems, the object of the present invention is to prevent the displacement of a thin plate to be held while holding a thin plate such as a photomask while preventing a pressing force above a certain level from acting on the thin plate to be held. An object of the present invention is to provide a thin plate holding device capable of absorbing, a photomask holding system having the device, and a conveying method.

In order to achieve the above object, the thin plate holding device of the present invention comprises:
A thin plate holding device having a pair of thin plate holding portions, wherein each of the pair of thin plate holding portions has a contact portion that comes into contact with a side surface or an end surface of the thin plate, and moves at least one of the corresponding contact portions. The pair of thin plate holding portions are positioned with the thin plate interposed therebetween so that the moving direction of the contact portion by the driving portion is oriented along the plane of the thin plate, and the distance between the pair of thin plate holding portions is In a device that holds a thin plate by narrowing
The contact portion includes a base portion and a contact main body that engages with the base portion in a form that is relatively movable along a moving direction of the drive portion,
Between the contact main body and the base portion, a first urging means for urging the contact main body in a direction to narrow the interval between the contact portions of the pair of thin plate holding portions is provided,
The base is provided with a locking portion that locks the abutting body,
Accordingly, when the thin plate is held by the pair of thin plate holding portions, a clearance is generated between the contact main body and the locking portion in either or both of the pair of thin plate holding portions. The positional deviation absorbing means for absorbing the positional deviation of the thin plate to be formed and the pressing force limiting means for limiting the pressing force acting on the side surface or the end face of the thin plate by the contact main body are formed.

According to the thin plate holding device of the present invention having the above-described configuration, the so-called horizontal compliance of the first urging means is used, so that when the thin plate is held from the side, the thin plate to be held is displaced. While absorbing, it is possible to limit the pressing force acting on the side surface or end surface of the thin plate, thereby avoiding adverse effects on the thin plate due to the retention of the thin plate.

More specifically, in a state where each of the pair of thin plate holding portions is arranged on each side of the thin plate to be held, the contact main body is changed to a thin plate arranged between the pair of thin plate holding portions by the first urging means. It is urged | biased toward and it is latched by the latching | locking part of a corresponding base. At this time, the contact portion is moved so as to narrow the interval between the corresponding contact portions of the pair of thin plate holding portions and is brought into contact with the side surface or end surface of the thin plate, so that the pressing force acting on both side surfaces or end surfaces can be obtained. It is possible to hold the thin plate from the side.

In this case, for example, due to the initial displacement in the horizontal direction of the thin plate, one thin plate holding portion of the pair of thin plate holding portions comes into contact with the side surface or the end surface of the thin plate before the other thin plate holding portion. In this case, even if the one thin plate holding portion continuously moves toward the other thin plate holding portion and moves further in the direction of increasing the pressing force after the other thin plate holding portion comes into contact with the side surface or the end surface of the thin plate, When the pressing force acting on the side surface or the end surface of the first urging force by the first urging means acting between the base portion of the pair of thin plate holding portions and the contact main body reaches one of the smaller urging forces, Only the base of the thin plate holding part on the small side continues to move toward the thin plate by the drive unit, while the corresponding contact body does not move further toward the thin plate, so that there is no gap between the contact main body and the locking part. Clearance begins to occur and the side of the sheet Or the pressing force acting on the end surface does not increase any more, it is possible to use a clearance resulting in a white misalignment absorbing horizontal.

The abutment main body further includes second urging means for urging the thin plate held in the vertical direction toward the initial holding position of the thin plate when the thin plate is held by the pair of thin plate holding portions. Is preferred.

Furthermore, it is preferable that the second urging means comprises a leaf spring extending along the moving direction of the contact portion by the driving portion.

In addition, it is preferable that the abutting main body further includes an elastic member that abuts on a side surface or an end surface of the thin plate to be held at a tip portion thereof.
In this case, the elastic member is an O-ring that can be attached to and detached from the abutting body, and the O-ring is preferably installed with the surface of the O-ring facing sideways.
Further, it is preferable that the driving units of the pair of thin plate holding units are driven in synchronization with each other.

Furthermore, by placing the point of action of the pressing force on the thin plate to be held by the elastic member offset from the center in the thickness direction of the leaf spring, the upper or lower side with respect to the thin plate to be held by the pressing force on the thin plate. A moment in the direction should be applied.
Furthermore, the first urging means may comprise a tension spring that urges the abutting body in a direction to draw the abutting body toward the base.

In addition, a guide is provided on the upper surface of the base, and a guided body guided by the guide is provided on the lower surface of the corresponding contact body. When a clearance is generated between them, the guided body may move along the guide.

In order to achieve the above object, a photomask holding system of the present invention comprises:
The thin plate to be held is a photomask placed on the base in a cassette consisting of a cover and a base,
A cassette vertical transport device for transporting a cassette containing a photomask in the vertical direction;
A cover holding device having a pair of cover holding portions, each cover holding portion having an abutting portion that abuts against an end surface of the cover, and a driving portion that moves the corresponding contacting portion in the horizontal direction. A cover holding device for holding the cover from the side by narrowing the interval between the corresponding contact parts of the pair of cover holding parts by the part;
A thin plate holding device according to any one of claims 1 to 9,
Each of the pair of thin plate holding portions has a drive portion that moves the corresponding contact portion,
Each of the pair of cover holding portions is positioned at a predetermined position on the side from a corresponding end surface of the cassette conveyed by the cassette vertical conveyance device,
In the thin plate holding device, each of the pair of thin plate holding portions is located below a corresponding cover holding portion at a predetermined position on the side from the end face of the photomask on the base transported by the cassette vertical transport device. It is set as the structure fixedly arranged so that it may be positioned.

According to the photomask holding device having the above-described configuration, when the photomask stored in the cassette is taken out and held, the contact portions of the pair of thin plate holding portions are moved by the driving portion. When the thin plate holding parts can move relative to each other so as to approach each other, one abutting part is fixed and the other abutting part moves toward one abutting part Compared to the above, it is possible to reduce the influence on the photomask when abutting. Further, the first urging means itself has both a position deviation absorbing means for absorbing the position deviation of the thin plate to be held and a pressing force limiting means for restricting the pressing force acting on the side surface or the end surface of the thin plate by the contact portion. By also serving, it can be effectively used for a photomask transported in a limited space.

In order to achieve the above object, a photomask transport method according to the present invention includes:
A method of taking out and transporting a photomask stored in a cassette having a cover and a base,
A step of exposing the photomask by holding the cover covering the photomask in a form sandwiched from both sides;
Holding the photomask on the base in a form that is sandwiched from both sides while utilizing horizontal compliance;
Moving the base downward from the photomask held from the side;
Supporting the photomask held from the side from below while utilizing the vertical compliance;
Releasing the holding of the photomask from the side;
Carrying a photomask supported from below;
It has composition which has.

According to the photomask transport method having the above configuration, the photomask exposed in the base is temporarily held from the side for taking out and transporting the photomask stored in the cassette. Then, after the base is moved downward, the photomask can be supported from below and transported as it is. At this time, when holding the photomask from the side and when transferring from the side holding to the lower support, the photomask is held or transferred while utilizing the horizontal or vertical compliance. It is possible to prevent sudden movements and impacts from being applied to.

Taking the case where the thin plate to be held is a photomask as an example, the photomask holding system of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic perspective view of a photomask holding system according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing one of a pair of thin plate holding portions and a pair of cassette holding portions of the photomask holding system according to the embodiment of the present invention. FIG. 3 is a partial perspective view showing the periphery of the drive unit of the pair of thin plate holding units of the photomask holding system according to the embodiment of the present invention. FIG. 4 is a schematic plan view showing the principle configuration of the thin plate holding device of the photomask holding system according to the embodiment of the present invention. FIG. 5 is a partial perspective view around the contact portion of the photomask holding system according to the embodiment of the present invention. FIG. 6 is a schematic side view around the abutting body of the photomask holding system according to the embodiment of the present invention. FIG. 7 is a schematic view showing the movement of the thin plate holding device of the photomask holding system according to the embodiment of the present invention. FIG. 8 is a view similar to FIG. 1 showing a state in which the cassette base is moved downward from the photomask held from the side by the cassette up-and-down conveyance device. FIG. 9 is a view similar to FIG. 1 showing a state in which a photomask is supported from below by a conventional transfer device.

In the present embodiment, a case where the photomask holding system of the present invention exhibits a delivery function to a conventional lower surface support type transfer apparatus D will be described as an example. More specifically, to remove the photomask from the cassette for processing the photomask, the photomask transport system of the present invention temporarily holds the photomask from the side, and then the lower surface of the photomask and the upper surface of the cassette base. A case where the bottom surface of the photomask is supported and conveyed using a conventional lower surface support type conveying device D between the two and the photomask is subjected to necessary processing and returned to the cassette will be described as an example.
Here, the conventional lower surface support type transfer device D has a pair of forks F extending in parallel to support the lower surface of the photomask, and the pair of forks F can be moved in the longitudinal direction of the forks F. I can do it.

The photomask is used for manufacturing a semiconductor device, a display device, an imaging device, etc., and forms a light-shielding film pattern on which a microfabricated light-shielding film pattern is formed on a transparent substrate. In order to form such a light-shielding film pattern In addition, it is necessary to transport between processing units to perform a plurality of processes. When transporting, the cassette CA is usually transported in a state of being accommodated in the cassette CA composed of the cover C and the base B. When performing necessary processing on the photomask P, It is taken out from the cassette CA. In order to position the photomask P at a predetermined position on the base B, a plurality of pins are usually provided on the base B according to the rectangular shape of the photomask P. In the present specification, the photomask P is used in a broad sense including a photomask blank and a photomask substrate which are materials of the photomask P on which a light shielding film is formed on a transparent substrate.

As shown in FIG. 1, a photomask P holding system 10 includes a cassette CA vertical transfer device 12, a cassette CA cover holding device 14, and a photomask arranged in alignment below the cover holding device 14. The P holding device 16 is schematically configured.

The cassette vertical transport device 12 includes a mounting table 18 that stably mounts the cassette CA at a predetermined position, a base portion 20 on which the mounting table 18 is attached, and a drive unit that moves the base portion 20 in the vertical direction (see FIG. Not shown). The drive unit is preferably a stepping motor. Thereby, it is possible to move the cassette CA mounted on the mounting table 18 in the vertical direction and position it at an arbitrary level within the resolution range of the stepping motor. In order to place the cassette CA at a predetermined position on the cassette CA, the end face of the cassette CA is arranged facing the cover holding device 14 and the holding device 16.

The cover holding device 14 has a pair of cover holding portions 22 arranged symmetrically with respect to the center line C of the mounting table 18 with the vertical conveying device 12 of the cassette CA interposed therebetween. Similarly, the holding device 16 for the photomask P includes a pair of thin plate holding portions 28 arranged symmetrically with respect to the center line C of the mounting table 18 with the vertical conveying device 12 for the cassette CA interposed therebetween. The pair of thin plate holding portions 28 is installed below the pair of cover holding portions 22.

As shown in FIG. 2, each of the pair of thin plate holding portions 28 includes a fixed base 30 and a first plate 11 having a U-shaped cross section fixed to the fixed base 30 with an open portion facing downward. On the other hand, each of the pair of cover holding portions 22 includes a second plate 13 provided in the same direction as the first plate 11, and both side portions of the second plate 13 are disposed above the first plate 11. A photomask holding device, which is provided in a nesting manner so as to extend downward from the upper surface of the first plate 11, and is described later between the upper surface of the first plate 11 and the U-shaped opening portion of the second plate 13. 16 and a pair of abutting main bodies 35 attached to the base 36 are provided, and an end of the second plate 13 facing the cassette CA is provided with a pair of abutments of a cover holding device 14 to be described later. A contact portion 24 is provided.

Each of the pair of cover holding portions 22 includes a contact portion 24 that contacts the end surface of the cover C, and a drive portion 26 that moves the contact portion 24. The drive unit 26 includes a rack 23 provided on the side surface of the second plate 13, and a pinion 29 that meshes with the rack 23 and is fixed to the rotary shaft 27 of the stepping motor 25. Through the pinion-rack mechanism, the second plate 13 and thus the pair of cover holding portions 22 can be moved with respect to the cassette. The pair of cover holding portions 22 are respectively placed on the mounting table 18 so that the cover C can be held from the side by moving the cover C in the direction in which the both contact portions 24 are brought closer to each other by the driving portion 26. Is positioned at a predetermined distance from the corresponding end surface of the cover C of the cassette CA placed on the cassette CA.

As shown in FIG. 3, each of the pair of thin plate holding portions 28 moves the fixed base 30, the contact portion 32 attached to the fixed base 30, and the contact portion 32 relative to the fixed base 30. And a drive unit 34.

The structure around the pair of thin plate holding portions 28 will be described in more detail with reference to FIGS. 4 and 5.
Each of the contact portions 32 includes a base portion 36 that is moved by a drive portion 34 that will be described later, and a pair of contact main bodies 35 that are attached to a rectangular lower surface 52 of the base portion 36. The base portion 36 is positioned such that a surface 39 facing the end surface of the photomask P placed on the placing table 18 is substantially parallel to each other. The arm 36 extends in an orthogonal direction and is attached to the base 36 so as to be parallel to each other. The pair of contact main bodies 35 are separated by a predetermined interval L. The length of the arms of each of the pair of contact main bodies 35 and the predetermined interval L may be appropriately set according to the size of the photomask P to be held. As a result, the pair of contact main bodies 35 are in contact with the end face of the photomask P whose level in the vertical direction is adjusted by the cassette vertical transfer device 12.

The driving unit 34 is schematically configured by a rack and pinion mechanism 40, a stepping motor 44 connected to the pinion 42 of the rack and pinion mechanism 40, and a control unit 46 of the stepping motor 44. The rack 48 of the rack and pinion mechanism 40 is provided on the base 36, while the pinion 42 and the stepping motor 44 are provided on the fixed base 30 (see FIG. 3), and the control unit 46 controls the amount of rotation of the stepping motor 44. Thus, the pinion 42 rotates according to the amount of rotation, and the rack 48 that meshes with the pinion 42, and thus the abutment main body that is locked to the locking portion 56 of the base portion 36 by the base portion 36 and the first urging means 46 described later. 35 moves together. In the control unit 46, the stepping motors 44 provided in each of the pair of thin plate holding units 28 are driven in synchronization with each other. Accordingly, the pair of thin plate holding portions 28 should be held so that the distance between the O-ring 50 (described later) provided on the contact main body 35 of the pair of thin plate holding portions 28 and the end face of the photomask P is the same. By positioning with respect to the photomask P, the respective contact main bodies 35 can be brought into contact with the corresponding end faces of the photomask P almost simultaneously.

Next, with reference to FIGS. 5 and 6, a description will be given of the periphery of the pair of contact main bodies 35. The base portion 36 has a lower surface 52 that faces the upper surface 51 of the contact main body 35. A guide 54 for guiding the contact main body 35 is provided so that the contact main body 35 can move relative to the base portion 36. The base portion 36 is provided with a locking portion 56 that contacts the contact main body 35. When the base portion 36 and the contact main body 35 are attracted to each other by a biasing force of a tension spring 46 described later, the contact main body 35 is locked. The portion 56 is locked.

On the other hand, the abutment main body 35 is provided with a guided body 58 fitted to the guide 54 on the upper surface 51, whereby the abutment main body 35 is guided to the base 54 while the guided body 58 is guided on the guide 54. It is possible to move relative to 36.

As shown in FIG. 5, the abutting body 35 has an elastic member 50 that abuts the end surface of the photomask P on the distal end portion 60 on the distal side from the base portion 36 in a direction orthogonal to the moving direction of the abutting body 35. Two are provided at a predetermined interval. Each elastic member 50 is composed of an O-ring, and is detachably attached to the contact main body 35 with the surface of the O-ring facing sideways. A conventionally known O-ring may be used. When the photomask P is held by the holding device 16, damage to the photomask P occurs when the isolated portion of the O-ring hits the end face of the photomask P. It is preferable that the material has elasticity that does not adversely affect by leaving a contact mark and a small inclusion ratio of impurities so as to satisfy clean performance. In this respect, for example, a perfluoroelastomer or a fluorine-based material is preferable as a rubber-based material. The interval between the two O-rings may be determined as appropriate in consideration of the ease of attaching and detaching each O-ring.

As shown in FIG. 4, when holding the photomask P using the pair of thin plate holding portions 28, the contact main bodies 35 of the pair of thin plate holding portions 28 are brought close to each other by the driving portion 34. The contact main body 35 is in contact with the end face of the photomask P so that the photomask P is supported by supporting eight points.

Referring again to FIGS. 5 and 6, a tension spring 46 is provided between the base portion 36 and the abutting body 35 to urge the base portion 36 and the abutting body 35 in the direction in which they are pulled toward each other. More specifically, one end is hooked to the bracket 31 provided on the base portion 36, and the other end is hooked to the bracket 33 provided on the side farther from the cassette CA than the bracket 31 with respect to the upper surface 51 of the contact main body 35. A tension spring 46 is provided. When the photomask P is held by the pair of thin plate holding portions 28, by arranging the pair of thin plate holding portions 28 on both sides of the photomask P, the respective contact main bodies 35 of the pair of thin plate holding portions 28 are The tension spring 46 is always urged toward the photomask P and is locked to the stopper 56. As a result, as will be described later, when there is a horizontal displacement of the photomask P, it is possible to absorb such displacement using the horizontal compliance of the so-called tension spring 46. At the same time, it is possible to limit the pressing force acting on the end face of the photomask P. The initial tensile force by the tension spring may be adjusted as appropriate in consideration of, for example, the weight of the photomask P to be held and conveyed, the pressing force applied to the photomask P, or the horizontal displacement offset described later. .

Each contact body 35 is provided with a leaf spring 64 extending along the moving direction of the contact body 35 by the stepping motor 44. When the photomask P is held by the pair of thin plate holding portions 28, the photomask The photomask P held toward the initial holding position of P is biased in the vertical direction. As a result, as will be described later, when there is a vertical displacement of the photomask P, it is possible to absorb such a positional displacement by utilizing so-called vertical compliance of the leaf spring. Note that the vertical rigidity may be determined as appropriate in relation to the size and weight of the photomask P to be held.

Further, as shown in FIG. 6, the action point of the pressing force F applied to the photomask P by the O-ring 50 is offset from the center in the thickness direction of the leaf spring 64. As a result, an upward moment M acts on the photomask P by the pressing force applied to the photomask P, and the photomask P can always be held up. Thus, as will be described later, when the photomask P is transferred from the holding device 16 from the side to a conventional transfer device supported from below, or from such a transfer device 16 to the base B of the cassette CA. It is possible to further reduce damage to the photomask P during delivery. The offset amount D1 may be determined in consideration of the magnitude of the moment to be applied in relation to the size and weight of the photomask P to be held.

The operation of the photomask P holding system 10 of the present invention having the above configuration will be described below with reference to FIGS.

First, in order to take out the photomask P stored in the cassette CA from the cassette CA, the cassette vertical cover device 12 moves the cover C of the cassette CA mounted on the mounting table 18 in the vertical direction. The holding device 14 positions the cover C at a level that can be held.

Next, the cover holding device 14 is driven to move each of the pair of cover holding portions 22 toward each other so as to hold the cover C from the side, take out the held cover C, and place it on the mounting table 18. The photomask P on the placed base B is exposed.

Next, the photomask P on the base B mounted on the mounting table 18 is finely adjusted in the vertical direction by the cassette vertical transfer device 12, and the level at which the photomask P can be held by the photomask P holding device 16. Position.
At this time, in each of the pair of thin plate holding portions 28, the contact main body 35 is urged toward the base portion 36, that is, the photomask P by the initial tensile force of the tension spring 46, and is locked by the stopper 56 of the base portion 36. It is in a state.

Next, by driving the stepping motors 44 in synchronization with each other by the control unit 46, as shown in FIG. 7A, the both abutting main bodies 35 of the pair of thin plate holding units 28 are brought closer to each other. Move relative to the base 36 of the.

Next, the isolated portion of the O-ring 50 starts to contact the end face of the photomask P. At this time, for example, as shown in FIG. 7B, the contact main body 35 of the left thin plate holding portion 28 has a corresponding end face of the photomask P ahead of the contact main body 35 of the right thin plate holding portion 28. Suppose that it comes into contact with
At this time, the left contact body 35 pushes the photomask P and moves it to the right in the drawing until the right contact body 35 contacts the right end surface of the photomask P.

Next, as shown in FIG. 7C, the right contact body 35 starts to contact the right end side surface of the photomask P. At this time, it is assumed that the tension force of the tension spring 46 of the left thin plate holding portion 28 is smaller than the tension force of the tension spring 46 of the right thin plate holding portion 28. For this reason, as shown in FIG. 7D, the base portion 36 of the left thin plate holding portion 28 continues to move toward the photomask P (to the right in the drawing) by the driving portion 34, while the contact main body 35. Since the guide member 58 follows the guide 54, a clearance (a in the drawing) is generated between the contact body 35 and the base portion 36 on the left side.
In this state, the photomask P itself is held by the clamping force corresponding to the pulling force of the smaller left tension spring 46 through both end faces, while the clearance generated in the left thin plate holding portion 28 has both tension forces. It is possible to move the photomask P with a force corresponding to the difference (in this case, in the right direction).
Therefore, when the photomask P is held by the pair of thin plate holding portions 28, the pressing force acting on the photomask P can be limited through use of the horizontal compliance of the tension spring 46 of both thin plate holding portions 28. In addition, it is possible to absorb the horizontal displacement by using the clearance generated between the contact main body 35 and the base portion 36.

Next, as shown in FIG. 8, in a state where the photomask P is held from the side, a conventional transfer device D is interposed between the lower surface of the photomask P and the upper surface of the base B by the cassette vertical transfer device 12. The base B is moved downward so that the fork F can be inserted.

Next, as shown in FIG. 9, the fork F of the conventional transfer device D arranged in a direction substantially orthogonal to the thin plate holding device 16 and the cover holding device 14 with respect to the photomask P It is inserted between the upper surface of B and the fork F is moved upward until it contacts the lower surface of the photomask P.
At this time, there is a level difference in the vertical direction between the pair of left and right forks F. For this reason, the right fork F contacts the lower surface of the photomask P before the left fork F. In this state, the photomask P is held from the side by the both abutting main bodies 35, and the leaf spring 64 of the right thin plate holding portion 28 begins to bend upward. By utilizing the vertical compliance of the leaf spring 64, it is possible to absorb the positional deviation in the vertical direction due to the bending of the leaf spring 64, thereby enabling stable delivery.
In particular, the contact portion of the O-ring 50 with the photomask P is offset upward with respect to the center of the plate spring 64 thickness, so that an upward moment M acts on the photomask P at all times. When F hits the lower surface of the photomask P while moving upward from below the photomask P, damage to the photomask P can be further reduced.

Next, when both forks F continue to move upward, the leaf spring 64 of the right thin plate holding portion 28 is further curved, while the left fork F starts to contact the lower surface of the photomask P. The photomask P is supported from below.

Next, the contact main body 35 of the pair of thin plate holding portions 28 is moved away from the end face of the photomask P, and delivery is performed.

Next, with the photomask P supported from below by both forks F, the photomask P is transported to a predetermined position by the conventional transport device D, and necessary processing is performed.

Next, the completed photomask P is returned to the base B of the cassette CA by using the conventional transfer device D again.
At this time, the reverse procedure to the case where the above-described photomask P is transferred from the thin plate holding device 16 to the conventional transfer device D is performed. That is, in a state where the photomask P is supported by the transport device D, the photomask P is held from the side by the pair of thin plate holding portions 28 to be transferred to the thin plate holding device 16 and further loaded by the cassette vertical transport device 12. The base B mounted on the mounting table 18 is moved upward, and the upper surface of the base B is brought into contact with the lower surface of the photomask P. At that time, similarly to the case where the photomask P is transferred from the thin plate holding device 16 to the transport device D, the vertical plate compliance of the leaf spring 64 is used to absorb the displacement in the vertical direction, and the thin plate holding device 16. At the time of delivery from the base to the base B, it is possible to avoid an abrupt movement or impact on the photomask P and an adverse effect on the photomask P.

While the embodiments of the present invention have been described in detail above, various modifications and changes can be made by those skilled in the art without departing from the scope of the present invention. For example, in the present embodiment, when the thin plate to be held is the photomask P, the thin plate holding device of the present invention has been described specifically for the case of exhibiting a delivery function to a conventional transfer device. Without being limited, for example, a circular semiconductor wafer substrate may be used in a form of supporting the side surface of the semiconductor wafer substrate using the holding device of the present invention. In this embodiment, the tension spring is used to use the horizontal compliance. However, the compression spring is used as long as the contact body is biased in the direction of narrowing the distance between the contact portions. May be. Furthermore, although it has been described that the two end faces of the photomask P are supported at eight points, the present invention is not limited to this, and for example, four-point support or two-point support depending on the size of the photomask P may be used. Furthermore, in the present embodiment, the thin plate holding device has been described as being fixed. However, the present invention is not limited thereto, and the thin plate holding device is movable, and the thin plate supported laterally by the thin plate holding device is used. The thin plate may be transported by moving together with the thin plate holding device.

As described above, according to the thin plate holding device, the photomask holding system and the conveying method according to the present invention, when holding a thin plate such as a photomask, a pressing force of a certain level or more acts on the thin plate to be held. In this way, it is possible to absorb the displacement of the thin plate to be held.

1 is a schematic perspective view of a photomask holding system according to an embodiment of the present invention. It is a schematic perspective view which shows one of a pair of thin plate holding | maintenance part and a pair of cassette holding | maintenance part of the holding system of the photomask which concerns on embodiment of this invention. It is a fragmentary perspective view which shows the surroundings of the drive part of a pair of thin plate holding | maintenance part of the holding system of the photomask which concerns on embodiment of this invention. It is a schematic plan view which shows the principle structure of the thin plate holding | maintenance apparatus of the photomask holding system which concerns on embodiment of this invention. It is a fragmentary perspective view around the contact part of the holding system of the photomask which concerns on embodiment of this invention. It is a schematic side view around the contact main body of the photomask holding system according to the embodiment of the present invention. It is the schematic which shows a motion of the thin plate holding | maintenance apparatus of the photomask holding system which concerns on embodiment of this invention. It is a figure similar to FIG. 1 which shows the state which moves the base of a cassette below from the photomask hold | maintained from the side by the cassette up-down direction conveying apparatus. It is a figure similar to FIG. 1 which shows the state which supports a photomask from the downward direction by the conventional conveying apparatus.

Explanation of symbols

P Photomask P
CA cassette
C cover
B base
F fork
D Conventional transport device
10 Photomask holding system
11 First plate
12 Vertical transfer device for cassette
13 Second plate 14 Cover holding device
16 Photomask holding device
18 Mounting base 20 Base
22 Cover holder
24 Contact part
26 Drive unit
28 Thin plate holder
30 Fixed base
31 Bracket
32 Contact part
33 Bracket
34 Drive unit
36 base
40 Rack and pinion mechanism 42 Pinion 44 Stepping motor 46 Control unit 48 Rack 52 Lower surface 51 Upper surface 54 Guide 56 Stopper 58 Guided body 60 Tip portion 50 Elastic member
64 leaf spring

Claims (11)

A thin plate holding device having a pair of thin plate holding portions, wherein each of the pair of thin plate holding portions has a contact portion that comes into contact with a side surface or an end surface of the thin plate, and moves at least one of the corresponding contact portions. The pair of thin plate holding portions are positioned with the thin plate interposed therebetween so that the moving direction of the contact portion by the driving portion is oriented along the plane of the thin plate, and the distance between the pair of thin plate holding portions is In a device that holds a thin plate by narrowing
The contact portion includes a base portion and a contact main body that engages with the base portion in a form that is relatively movable along a moving direction of the drive portion,
Between the contact main body and the base, a first urging means for urging the contact main body in a direction to narrow the interval between the two contact portions of the pair of thin plate holding portions is provided.
The base is provided with a locking portion that locks the abutting body,
Accordingly, when the thin plate is held by the pair of thin plate holding portions, a clearance is generated between the contact main body and the locking portion in either or both of the pair of thin plate holding portions. The thin plate is characterized in that it includes a position shift absorbing means for absorbing a position shift of the thin plate to be formed, and a pressing force limiting means for limiting a pressing force acting on a side surface or an end surface of the thin plate by the contact body. Holding device.       The contact body further includes second urging means for urging the thin plate held in the vertical direction toward the initial holding position of the thin plate when the thin plate is held by the pair of thin plate holding portions. The thin plate holding device according to 1. 3. The thin plate holding device according to claim 2, wherein the second urging unit includes a plate spring extending along a moving direction of the contact portion by the driving unit. The thin plate holding device according to any one of claims 1 to 3, wherein the contact main body further includes an elastic member that contacts a side surface or an end surface of the thin plate to be held at a tip portion thereof. The thin plate holding device according to claim 4, wherein the elastic member is an O-ring that can be attached to and detached from the abutting body, and the O-ring is installed with a surface of the O-ring facing sideways. The thin plate holding device according to claim 1, wherein the driving unit is provided in each of the pair of thin plate holding units, and the both driving units are driven in synchronization with each other. The point of action of the pressing force on the thin plate to be held by the elastic member is offset from the center in the thickness direction of the leaf spring, thereby upward or downward with respect to the thin plate to be held by the pressing force on the thin plate. The thin plate holding device according to claim 3, wherein the moment is applied. 2. The thin plate holding device according to claim 1, wherein the first urging unit includes a tension spring that urges the abutting body in a direction of pulling the abutting body toward the base. 3.     A guide is provided on the surface of the base portion, and a guided body guided by the guide is provided on the corresponding surface of the contact body, and a clearance is provided between the contact body and the locking portion. The thin plate holding device according to claim 1, wherein the guided body moves along the guide when the phenomenon occurs. The thin plate to be held is a photomask placed on the base in a cassette consisting of a cover and a base,
A cassette vertical transport device for transporting a cassette containing a photomask in the vertical direction;
A cover holding device having a pair of cover holding portions, each cover holding portion having an abutting portion that abuts against an end surface of the cover, and a driving portion that moves the corresponding contacting portion in the horizontal direction. A cover holding device for holding the cover from the side by narrowing the interval between the corresponding contact parts of the pair of cover holding parts by the part;
A thin plate holding device according to any one of claims 1 to 7,
Each of the pair of thin plate holding portions has a drive portion that moves the corresponding contact portion,
Each of the pair of cover holding portions is positioned at a predetermined position on the side from a corresponding end surface of the cassette conveyed by the cassette vertical conveyance device,
In the thin plate holding device, each of the pair of thin plate holding portions is located below a corresponding cover holding portion at a predetermined position on the side from the end face of the photomask on the base transported by the cassette vertical transport device. Fixedly positioned to be positioned,
A photomask holding system. A method of taking out and transporting a photomask stored in a cassette having a cover and a base,
A step of exposing the photomask by holding the cover covering the photomask in a form sandwiched from both sides;
Holding the photomask on the base in a form that is sandwiched from both sides while utilizing horizontal compliance;
Moving the base downward from the photomask held from the side;
Supporting the photomask held from the side from below while utilizing the vertical compliance;
Releasing the holding of the photomask from the side;
Carrying a photomask supported from below;
A method of transporting a photomask, comprising: