JP2002164424A - Wafer holding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer holding apparatus where the flatness of a wafer held on a chuck table is improved and replacement of the chuck table can be carried out easily. SOLUTION: This wafer holding apparatus 10 comprises a clamp means for securing the chuck table 16 in the apparatus main body 14 releasably. The clamp means comprises a clamper 30 that can move vertically, and is constituted so as to mount the apparatus main body 14 with the chuck table 16 by forcing the pawl 26 on a pawl bearing part 66 by lowering the clamper 30 by inserting a pawl 26 provided on a lower surface of the chuck table 16 between the pawl bearing part 66 formed on the apparatus main body 14 and a point of the clamper 30 spaced above from that.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer holding apparatus for sucking and holding a wafer on a suction table attached to an upper surface of an apparatus body.

[0002]

2. Description of the Related Art A wafer profiler (wafer surface shape measuring device) and a film thickness measuring device used for inspecting an intermediate product of a semiconductor are provided with a suction table or chuck for holding a wafer during inspection or measurement. A wafer holding device including a table is provided, and the wafer is suctioned and held on the suction table by suctioning the wafer through the suction table under negative pressure.

[0003] In these wafer profilers and film thickness measuring machines, very high flatness is required for the surface of the wafer held on the suction table. However,
It is necessary to provide an air pocket on the surface of the suction table to apply a negative pressure to the wafer. When a wafer is suctioned on the suction table, the portion of the wafer corresponding to the air pocket is likely to be dented, and the flatness of the wafer is reduced. Can be adversely affected. Therefore, in order to arrange the air pockets as uniformly as possible over the entire suction table, a pin chuck type suction table that holds a wafer on a very large number of pins and applies a negative pressure to the wafer is often used.

[0004] The term "flatness" used in the present application means the degree of shape change due to a secondary factor given to the wafer surface when holding the wafer. That is,
The high flatness of the held wafer means that the wafer is held in a state where the actual surface shape of the wafer can be measured more accurately.

[0005]

In the above-described wafer holding apparatus, the apparatus main body and the suction table are formed separately, and are mounted and fixed to the apparatus main body by fasteners such as bolts. For this reason, it is necessary to provide a bolt hole on the surface of the suction table in order to fix the suction table to the apparatus main body by, for example, a bolt. As a result, a pin cannot be arranged in the bolt hole portion, and there is a problem that the wafer sucked and held thereon tends to be dented in this portion.

Further, dust and the like from the wafer accumulate on the surface of the suction table, that is, on the tips of the pins as the device is used. Therefore, in a wafer profiler or a film thickness measuring machine which requires a high flatness for holding a wafer, it is necessary to replace an attached suction table for cleaning or replacement of parts. However, as described above, if the apparatus is fixed to the apparatus main body by a fastener such as a bolt, a problem occurs that a long time is required for replacement work such as removal of the bolt. Furthermore, when fixing to the device body with fasteners after replacing the suction table,
Chuck surface (suction surface) with subtle strength of fastening of fastener
There is also a problem that the horizontality of the camera tends to collapse, and the adjustment requires much more time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above problems, improve the flatness of a wafer held on a suction table, facilitate replacement of a suction table, and easily level a chuck surface. It is an object of the present invention to provide a wafer holding device capable of reducing the number of wafers.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned object, the present invention is configured so that a suction table can be mounted on an apparatus main body without using fasteners such as bolts. That is,
According to the present invention, there is provided a wafer holding device for sucking and holding a wafer on a suction table attached to an upper surface of an apparatus main body, comprising a fastening means for detachably attaching the suction table to the apparatus main body. A clamp provided on the lower surface of the suction table, wherein a clamp provided on a lower surface of the suction table and a clamper spaced upwardly from the pawl support; There is provided a wafer holding device in which the claw is pressed onto the claw support by inserting the claw into the space between the claw support and the tip and lowering the clamper.

In the above-mentioned wafer holding device, it is preferable that the tightening means includes a spring for urging the clamper downward, and the claw is pressed onto the claw support by only a spring force. More preferably, the tightening means further includes a cylinder device for raising the clamper against the spring force. Further, it is preferable that three pawls are provided on the lower surface of the suction table at equal intervals around the rotation axis of the suction table.

Further, the tightening means has an upwardly projecting distal end provided with a negative pressure suction port, and when the suction table is attached to the apparatus main body, the negative pressure suction passage of the suction table is connected to the negative pressure suction passage. It is preferable that the suction port is automatically connected to the suction port. The suction table is mounted on the device body by clamping the claws provided on the lower surface of the suction table between the claw support formed on the device main body and the clamper provided separately therefrom, so that the suction table is Fasteners such as bolts for fixing to the apparatus main body become unnecessary. Therefore, it is not necessary to provide a bolt hole or the like on the suction table, and the negative pressure can be applied more uniformly to the wafer held on the suction table, and the flatness of the wafer can be improved.

Further, since the suction table can be mounted on the apparatus main body only by disposing the nail between the nail support portion and the clamper and lowering the clamper, the replacement operation is very easy. Furthermore, the horizontality and vertical position of the suction table (especially its chuck surface) can be determined by the claw support on the apparatus main body, and the clamping force acting on the clamper by the clamping means is equally applied to each claw. Therefore, the chuck surface of the suction table can be easily arranged horizontally.

If the tightening force by the tightening means is realized by a spring, the reproducibility of the tightening force is enhanced, and the state is substantially the same before and after the suction table is replaced (the vertical position of the chuck surface, etc.).
The suction table can be attached to the apparatus body.
In addition, when the suction table is attached to the apparatus main body, if the negative pressure suction passage of the suction table is automatically connected to the negative pressure suction port, the operation of connecting the negative pressure suction passage is also omitted. The replacement work can be further simplified. This is made possible only by the wafer holding device of the present invention in which the mounting position on the device main body is defined by the claws.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part of the wafer holding device of the present invention, and FIG. 2 is a view of the wafer holding device of FIG. FIG. 3 is a perspective view showing a first embodiment of a claw provided on the suction table of the wafer holding device shown in FIG. 1, and FIG. 4 shows a second embodiment of the claw. It is a perspective view.

Referring to FIGS. 1 and 2, the wafer holding apparatus 10 includes a base 12, an apparatus main body 14 supported by the base 12, and a suction table 16 mounted on the upper surface of the apparatus main body 14. . The upper surface of the suction table 16 includes a holding area where a number of wafer support pins 18 are erected, and a rim 20 extending upward to the same height as the tip of the wafer support pins 18 around the holding area. Thus, the negative pressure is sucked through the negative pressure suction passage 22 provided in the suction table 16 to apply a negative pressure to the holding area, so that the wafer 24 can be sucked and held on the holding area. A claw 26 is provided on the lower surface of the suction table 16 as described later. In FIG. 2,
The wafer support pins 18 have been omitted for simplicity.

The apparatus main body 14 includes a support portion 14a fixedly supported on the base 12, and a rotating portion 14b rotatable with respect to the support portion 14a via a bearing 28. The rotation unit 14b is rotated by a rotation drive device (not shown) such as a motor. As the bearing 28, an appropriate bearing such as a ball bearing or a roller bearing is used.

In a conventional wafer holding apparatus, a fastener such as a bolt has been used to attach the suction table to the apparatus main body. The wafer holding device 10 of the present invention includes a tightening means in the rotating portion 14b instead of such a fastener. The clamping means is provided above the apparatus main body 14 (therefore, above the rotating part 14b) and is movable vertically with respect to the rotating part 14b of the apparatus main body 14.
0 and an actuator 32 for moving the clamper 30 in the vertical direction with respect to the rotating part 14b. As shown in FIG. 2, the clamper 30 has a shape including a substantially circular central portion 30a and a protruding portion 30b extending radially outward from a peripheral edge thereof.

In the embodiment shown in FIG. 1, the actuator 32 extends vertically along the rotation axis 34 of the rotating part 14b and is slidable with respect to the rotating part 14b of the apparatus body 14. A rod 36 is provided. A radially extending flange portion 36a is provided at the upper end of the rod 36, and the flange portion 36a is connected to the clamper 30 via a spherical washer or a spherical joint 38. A negative pressure supply passage 40 is provided in the center of the rod 36 along the axial direction.

The rod 36 is rotatably connected to a pipe joint 42 at a base end (an end located on the base 12 side) of the negative pressure supply passage 40, and is connected to the pipe joint 42 and the pipe joint 42. The pipe 44 communicates with a negative pressure suction source. On the other hand, the rod 36 protrudes upward beyond the clamper 30 at the distal end (the end located on the suction table 16 side) of the negative pressure supply passage 40 and projects upward, such as a simple coupling having a negative pressure suction port 46. A part 48 is provided. When the suction table 16 is mounted on the apparatus main body 14,
It is preferable that the negative pressure suction passage 22 of the suction table 16 be automatically connected to the negative pressure suction port 46 of the upward projecting tip 48.

The tightening means further includes a spring 50 for urging the clamper 30 and the rod 36 downward, and a cylinder device for raising the clamper 30 and the rod 36 against the spring force. In the embodiment shown in FIG. 1, the rod 36 is disposed within the rotating portion 14 b of the device body 14.
A spring chamber is provided around the, and a spring 50 installed in the spring chamber urges the rod 36 downward. Further, in the embodiment shown in FIG.
4, that is, the device body 14
A piston chamber 52 is formed in the rotating part 14b (specifically, the rotating part 14b), and a piston 54 is inserted therein. As a result, when the piston 54 of the cylinder device rises, it comes into contact with the lower surface of the central portion 30a of the clamper 30 and the shoulder provided on the peripheral surface of the rod 36, and the rod 36 and the clamper 30
Can be raised against the spring force (the biasing force of the spring 50). In the embodiment shown in FIG. 1, a seal 56 is provided so that air does not leak from between the piston 54 and the wall surface of the piston chamber 52.

In the embodiment shown in FIG. 1, the downward movement of the rod 36 is performed by using the biasing force of the spring 50. However, the cylinder apparatus is also used for the downward movement of the rod 36. Is possible. Further, in the embodiment shown in FIG. 1, a cylinder device formed integrally with the device main body 14 is used, but a cylinder device separate from the device main body 14 may be used. It is.
Further, another mechanism can be used as the actuator 32.

The advantage of using the spring 50 is that there is little variation in the spring force (ie, the tightening force) acting on the clamper 30 via the rod 36. Therefore,
The tightening force of the clamper 30 corresponding to the screw tightening force in the conventional wafer holding device has less variation between replacement operations and between operators, and the level of the chuck surface of the suction table 16 is guaranteed with high accuracy. Because

In order to supply compressed air to the piston chamber 52 of the cylinder device, the stationary support portion 14a of the device body 14 is provided.
The first air supply passage 58 is provided in the
The movable rotary part 14b is provided with a second air supply passage 60 communicating with the piston chamber 52, and the support part 14a and the rotary part 14 are provided.
An annular communication passage 62 is provided between the first and second members b and b so that they can always communicate even when rotated. Further, seals 64 are provided on both sides of the boundary between the support portion 14a and the rotating portion 14b in order to prevent air from leaking from the communication passage 62.

The rotating portion 14b of the apparatus main body 14 is provided with a claw support 66 opposed to the tip of the clamper 30 provided above the apparatus main body 14, that is, the protruding portion 30b. The portion is spaced from the pawl support 66. The suction table 1 is inserted into a gap formed between the claw support 66 and the tip of the clamper 30.
6, the clamper 30 is moved down to narrow the gap, thereby clamping the claw 26 of the suction table 16, thereby moving the suction table 16 to the apparatus body 14.
(Specifically, the rotating part 14b).

Referring to FIG. 1, the pawl bearing 66 includes a height adjusting means 68 and a spherical washer 70 provided on the height adjusting means 68. The height adjusting means 68 includes, for example, a lower member 68a having an upper slope, an upper member 68b having a slope corresponding to the lower surface, and a screw 68c engaged with the lower member 68a. Consists of In this case, by rotating the screw, the lower member 68a moves relatively to the upper member 68b, and the upper member 68b
The height of the upper surface can be changed. Of course, other suitable height adjustment means can be used.

Since the clamping force of the clamping table 16 is substantially constant, the clamp 26 presses the claws 26 of the suction table 16 against the pawl support portions 66 to make contact with the vertical position and the vertical position. The level of the chuck surface is determined. Further, even when the chuck surface is not horizontal when the suction table 16 is attached to the apparatus main body 14, or when the vertical position of the chuck surface is changed, each of the claw support portions is controlled by the height adjusting means 68. By changing the height of the top surface of the chuck 66, the horizontality and the vertical position of the chuck surface can be easily adjusted.
Further, by using the spherical washer 70 for the claw support portion 66, even if the surface defined by the suction table 16 is inclined due to individual differences in the height of the claw 26 of the suction table 16, the suction table 16 and the claw 26 thereof may be used. An extra load is applied, and no deformation occurs. The spherical washer or the spherical joint 38 used for the joint between the rod 36 of the fastening means and the clamper 30 has the same effect.

Since the chuck surface of the suction table 16 is determined by the claw 26 and the claw support portion 66, three claw support portions 66 are provided on the apparatus main body 14 and three claw 26 are provided on the lower surface of the suction table 16. preferable. More preferably, the three claws 26 and the pawl bearings 66 are arranged at equal intervals about the rotation axis 34. The claw 26 may be formed by a member separate from the suction table 16 or may be formed integrally with the suction table 16.

Referring to FIGS. 3 and 4, an embodiment of the claw 26 provided on the lower surface of the suction table 16 is shown. The claw 26 provided on the suction table 16 is provided with a vertical portion 26 extending substantially vertically from the lower surface of the suction table 16.
a, a horizontal portion 26b facing the lower surface of the suction table 16 and extending in a substantially horizontal direction, and a horizontal portion 2b.
It includes a contact portion 26c extending downward from 6b and contacting the spherical washer 70 of the claw support portion 66, and has a substantially L-shaped vertical cross section.

As shown in FIG. 3, the pawl 26 preferably further includes a vertically extending stop wall 26d on its side. However, as shown in FIG. 4, the stop wall 26d may not be provided. In the wafer holding device 10 shown in FIGS. 1 and 2, a claw 26 of the type shown in FIG. 3 is used. Next, a procedure for attaching and detaching the suction table 16 in the wafer holding device 10 shown in FIGS. 1 and 2 will be described.

First, a procedure for mounting the suction table 16 on the apparatus main body 14 of the wafer holding apparatus 10 will be described. First, by supplying compressed air from a compressed air source to the cylinder device of the actuating device 32, the clamper 30 of the tightening means is raised against the spring force, and the tip of the clamper 30, ie, the protruding portion 30b, and the pawl support The gap between the upper surface and the upper surface of 66 is widened.

Next, the surface of the suction table 16 provided with the claws 26 (that is, the surface opposite to the chuck surface) is attached to the apparatus body 14.
, The claw 26 of the suction table 16 is aligned with the notch between the adjacent protruding portions 30 b of the clamper 30, and the suction table 16 is moved closer to the apparatus main body 14. In this position, since the claw 26 does not interfere with the clamper 30, the claw 26 of the suction table 16 can be closer to the rotating portion 14b of the apparatus body 14 than the clamper 30.

Next, the upper surface of the pawl support 66 formed on the apparatus body 14 (ie, the upper surface of the spherical washer 70) and the tip of the clamper 30 spaced upward from the pawl support 66 (protruding portion 30b). Between the claws 26 of the suction table 16
The suction table 16 is rotated until is inserted. Since the nail 26 shown in FIG. 3 is used, the nail 26
The suction table 16 with respect to the apparatus main body 14 is positioned by bringing the protruding portion 30b, which is the tip end of the clamper 30, into contact with the stop wall 26d.

After the pawl 26 is inserted between the tip of the clamper 30 and the pawl support 66, the fluid (in this case, air) is discharged from the piston chamber 52 of the cylinder device, and the clamper is biased by the spring 50. The claw 26 is clamped between the tip of the clamper 30 and the claw support 66. As a result, the suction table 16 is rotated by the rotating portion 14b of the apparatus main body 14.
Fixedly attached to

When the suction table 16 is mounted on the rotating portion 14b of the apparatus main body 14, the negative pressure suction passage 22 provided in the suction table 16 is connected to the negative pressure suction port of the upwardly projecting distal end portion 48 provided in the fastening means. 46 is automatically connected.
Therefore, the negative pressure can be suctioned by the negative pressure suction source to apply a negative pressure to the wafer 24 placed on the chuck surface of the suction table 16 and suction the wafer 24 there.

If the chuck surface is not horizontal when the suction table 16 is mounted on the apparatus main body 14, the height adjusting means 68 of the claw support portion 66 adjusts the height (vertical height) of the spherical washer 70 of the claw support portion 66. , The horizontality and the vertical position of the chuck surface can be easily adjusted. Further, since the clamper 30 tightens the claw 26 with a uniform tightening force of the spring 50 every time the clamper 30 is tightened, once the height of the upper surface of the claw support portion 66 is adjusted by the height adjusting means 68, the chuck of the suction table 16 is adjusted. The surface is a nail 26
Is pressed against the claw support 66 by the clamper 30 to be uniquely determined. Therefore, the difference in the horizontality of the chuck surface and the vertical position thereof does not occur by the operator.

Further, by lowering the clamper 30, all the claws 26 (three in this case) are simultaneously pressed against the claw support 66 with the same tightening force, so that the chuck surface of the suction table 16 can be accurately positioned. In addition to being able to be horizontal, the work of attaching and detaching the suction table 16 can be easily performed. When removing the suction table 16 held by the rotating portion 14b of the apparatus body 14, the above procedure may be reversed.

While the wafer holding device 10 of the present invention has been described with reference to the illustrated embodiment, other embodiments are also included in the scope of the present invention. For example, the protrusion of the clamper may be moved in the radial direction of the suction table to engage with the claw of the suction table. Also,
The number of claws may be less than three or more than three. For example, it is possible to mount the suction table on the apparatus main body with only a single claw having a substantially semicircular shape. The shape of the clamper can also take various shapes other than the illustrated shape.

[0037]

As described above, according to the present invention, the suction table can be mounted on the apparatus body without using fasteners such as bolts in the wafer holding apparatus. For example, there is no region where the wafer support pins cannot be provided, and the flatness of the wafer held on the suction table can be improved. Further, the suction table is mounted on the device main body only by pressing the claw of the suction table against the claw support portion of the device main body by the tip of the clamper, and the clamping by the clamper is performed by the tightening means provided in the device main body. In addition, the work of replacing and removing the chuck table becomes easy.
In addition, there is almost no difference between the workers regarding the adjustment of the level of the chuck surface of the suction table, and the horizontal chuck surface can be supplied stably.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a wafer holding device of the present invention.

FIG. 2 is an arrow view of the wafer holding device of FIG. 1;

FIG. 3 is a perspective view showing a first embodiment of a claw provided on a suction table of the wafer holding device shown in FIG. 1;

FIG. 4 is a perspective view showing a second embodiment of a nail provided on a suction table.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer holding device 14 ... Device main body 14a ... Support part 14b ... Rotating part 16 ... Suction table 22 ... Negative pressure suction passage 24 ... Wafer 26 ... Claw 26a ... Vertical part 26b ... Horizontal part 26c ... Contact part 26d ... Stop wall DESCRIPTION OF SYMBOLS 30 ... Clamper 30a ... Central part 30b ... Protrusion part 32 ... Actuator 34 ... Rotation axis 36 ... Rod 46 ... Negative pressure suction port 48 ... Top end part 50 ... Spring 52 ... Piston chamber 54 ... Piston 66 ... Claw support part

Claims (5)

[Claims] 1. A wafer holding device for sucking and holding a wafer on a suction table attached to an upper surface of an apparatus main body, comprising: a fastening unit for detachably attaching the suction table to the apparatus main body; The tightening means includes a clamper that can move in a vertical direction, and a claw provided on a lower surface of the suction table has a claw support formed on the apparatus main body and a tip of a clamper spaced upward from the claw support. A wafer holding device, wherein the claw is pressed onto the claw support by inserting the claw into the space and lowering the clamper. 2. The wafer holding device according to claim 1, wherein said tightening means includes a spring for urging said clamper downward, and said claw is pressed onto said claw support portion only by a spring force. 3. The wafer holding device according to claim 2, wherein said tightening means further comprises a cylinder device for raising said clamper against said spring force. 4. The wafer holding device according to claim 1, wherein three of said claws are provided on a lower surface of said suction table at equal intervals around a rotation axis of said suction table. 5. The suction means has an upwardly projecting distal end provided with a negative pressure suction port, and when the suction table is attached to the apparatus main body, the negative pressure suction passage of the suction table is connected to the negative pressure suction passage. The wafer holding device according to claim 1, wherein the wafer holding device is automatically connected to a suction port.