JP2645135B2 - Semiconductor wafer holding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a semiconductor wafer holding device used in a step of cleaning a semiconductor wafer.

(Prior Art) When manufacturing a semiconductor device, many processing steps are required. Among these steps, a scrub step for removing unnecessary substances such as dust attached to the surface of a semiconductor wafer is important. There is.

In this step, first, unnecessary substances on the surface of the semiconductor wafer are rubbed with, for example, a rotating brush and then washed with pure water. After that, it is necessary to drop water droplets on the wafer surface. Conventionally, a holding device as shown in FIG. 5 and its plan view, FIG. 6, has been used.

The semiconductor wafer 1 transported by a transport mechanism (not shown) is guided into the processing container 3 and placed on the chuck body 42. A hole 42a is provided on the upper surface of the chuck body 42, and an air passage 43 communicating with the hole 42a is provided inside. This passage is connected to a vacuum device (not shown) via a vacuum tube 41, and the inside air is exhausted to generate a negative pressure, so that the semiconductor wafer 1 is moved to the chuck body 42.
Is adsorbed on the upper surface. Then, the semiconductor wafer 1 is rotated as shown by the arrow by the drive motor 5 connected to the chuck body 42, and water droplets on the wafer surface are removed by centrifugal force.

(Problems to be Solved by the Invention) However, there is a limit to the attraction force due to the vacuum pressure, and when the vacuum pressure provided by the vacuum device is reduced, the holding force of the semiconductor wafer 1 is also reduced, which may cause instability. there were.

Further, even if the diameter of the semiconductor wafer 1 is increased, there is a limit in relation to the holding force.

Further, when not only the front surface but also the back surface of the semiconductor wafer 1 is cleaned, water droplets adhere to the back surface of the wafer, but it is impossible to remove the water droplets in the portion in contact with the chuck body 42. In addition, the water droplets on the back side
The air passage 43 is sucked from the hole 42a of the semiconductor wafer 1 and accumulates inside the vacuum tube 41, and the suction force is reduced.
May fall off the chuck body 42 and be damaged.
For this reason, conventionally, there was a problem that only one surface of the semiconductor wafer 1 could be cleaned.

In view of the above circumstances, an object of the present invention is to provide a semiconductor wafer holding device that can hold a semiconductor wafer securely and can wash not only one surface but also both surfaces.

[Configuration of the invention]

(Means for Solving the Problems) A semiconductor wafer holding device of the present invention is inserted into a chuck body having at least two air cylinders positioned so as to face each other in the radial direction, A piston that moves in the radial direction, an elastic body that presses the piston inward in the radial direction, a chuck claw that is fixed to the piston protruding from the chuck body and has a similar concave portion, A compressor that feeds compressed air that is pressed toward the chuck body, and a chuck body support that supports the chuck body, so that the semiconductor wafer is held inside the chuck claws so that the semiconductor wafer is held at a position away from the surface of the chuck body. It is characterized in that a concave portion for supporting the outer edge portion is provided in each.

Here, the chuck pawl may have a counterweight that is provided on the opposite side of the rotation center and generates a centrifugal force having a direction different from that of the chuck pawl due to rotation.

Further, a flat plate that rotates together with the chuck body, a sensor unit provided on the rotation circumference of the flat plate to detect a predetermined position on the flat plate, and a sensor unit that detects this position after the rotation of the rotation driving unit stops. And a stop position control unit that stops the chuck main body in a fixed direction by rotating the chuck main body until the operation is completed.

(Operation) The outer edge of the semiconductor wafer is supported by the concave portion of the chuck claw, and the chuck claw is pressed by the elastic body in the radial direction and moves, thereby holding the semiconductor wafer at a position away from the surface of the chuck body. . As a result, the semiconductor wafer is held by the mechanical elastic force in a state where only the outer edge portion is in contact with another one.

Thereafter, when compressed air is sent into the cylinder by the compressor, the piston fixed to the chuck pawl is pressed radially outward and moves in the cylinder, thereby releasing the holding of the semiconductor wafer.

The chuck jaws try to open radially outward due to centrifugal force during rotation, but due to the presence of the counterweight, centrifugal forces in different directions are generated and offset, and the semiconductor wafer does not fall off the chuck jaws.

When the stop unit is rotated and stopped by the stop position control unit until the sensor unit detects a predetermined position on the flat plate, the stop position of the chuck unit is directed in a certain direction.

(Example) Hereinafter, a first example which is an example of the present invention will be described with reference to FIG. 1 and FIG. 2 which is a plan view thereof.
While the above-described conventional apparatus sucks and holds the back surface of the semiconductor wafer 1 by using the suction force of the vacuum pressure, in the present embodiment, the outer edge of the wafer 1 is formed by using the mechanical elastic force. The difference is that it is held so as to be sandwiched from both sides.

By the chuck body support 17 fixed on the table 18,
The chuck body 11 is supported so as to rotate.

The chuck body 11 has the following components. The chuck claws 12a and 12b are provided so as to face each other, and engage the outer edges of the semiconductor wafer 1 with the concave portions 12c and 12d to support the semiconductor wafer 1 from both sides. This chuck claw 12a,
Pistons 21a and 21b respectively connected to 12b move radially in the air cylinders 14a and 14b, respectively.
It is pressed inward in the radial direction by compression springs 15a and 15b as elastic bodies. The air passages 23 are air cylinders 14a, 14
and a tube connecting the air tube 4 and the air tube 4 to allow compressed air from a compressor (not shown) connected to the air tube 4 to pass in the direction of the arrow to form air cylinders 14a and 14b.
To be sent in. The air seal 19 prevents compressed air from leaking from between the chuck body support 17 and the air passage 16.

The motor 5 rotates the chuck body 11 similarly to the conventional apparatus, and the processing container 3 receives the cleaning liquid.

The operation of the present embodiment having such a configuration will be described. The semiconductor wafer 1 transported by a transport unit (not shown) is transferred to a chuck body in the processing chamber 3.
Guided to the top of 11. At this stage, the compressed air is sent into the air cylinders 14a and 14b through the air tube 4 and the air passage 16, and the air pressure is greater than the elastic force of the compression springs 15a and 15b, and the pistons 21a and 21b are moved outward in the radial direction. Have moved towards. As a result, the chuck claws 12a and 12b are at the positions indicated by the dashed lines,
Is wider than the diameter.

The semiconductor wafer 1 is moved downward by the transport means,
The guide is guided to the positions of the concave portions 12c and 12d of the chuck claws 12a and 12b.
Thereafter, when the supply of the compressed air from the compressor is stopped, the air pressure in the air cylinders 14a, 14b returns to the atmospheric pressure, and the action of the compression springs 15a, 15b causes the chuck claws 12a, 12b to move radially inward. And the outer edge of the semiconductor wafer 1 is held from both ends.

Thereafter, the chuck body 11 is rotated by the rotation of the motor 5, and water droplets adhering to the surface of the semiconductor wafer 1 are removed.
It is shaken off by centrifugal force and removed.

In this case, a centrifugal force is applied to the chuck claws 12a and 12b to move away from each other, but a counterweight is provided to prevent this. Chuck claw 12a
Have counterweights 13a and 13c, chuck jaws 12b
Have counterweights 13b and 13d as their centers of rotation
Since it is installed on the opposite side of 22, the centrifugal force works in the opposite direction and cancels out. As a result, the chuck claws 12a and 12b do not spread outward, and the semiconductor wafer 1 is prevented from falling off.

When the compressed air is sent into the air cylinders 14a and 14b again after removing the water droplets, the chuck claws 12a and 12b are opened outward, and the holding of the semiconductor wafer 1 is released.

As described above, according to the first embodiment, the holding force is high because the outer edge portion of the semiconductor wafer 1 is held between both ends by the mechanical elastic force, and the holding force is high, as in the case where the semiconductor wafer 1 is sucked by the vacuum pressure. Problems such as a decrease in holding power are solved. Therefore, it is possible to cope with an increase in the diameter of the semiconductor wafer.

Further, since the wafer is held only at the outer edge portion, not only the front surface but also the water droplet on the back surface can be removed, and both sides of the semiconductor wafer can be cleaned.

Further, by sending the compressed air into the air cylinders 14a and 14b, the holding of the wafer can be easily released, so that the workability can be improved.

Next, a second embodiment will be described with reference to FIG. 3 showing its structure and FIG. 4 which is a plan view thereof.

This embodiment is different from the first embodiment in that the guide rail 42 and the chuck unit 11 in the transfer device do not interfere with each other.
It further has a stop position control unit for making the stop direction of the chuck body 11 constant. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The guide rail 42 is for carrying the semiconductor wafer 1 on it. The guide rail 42 is at a narrow position B between the guide rails during the transfer, and moves parallel to the position A after the transfer. The disk 9 is connected to the rotating shaft 5a of the motor 5, and has a groove 31a on the circumference. The sensor 32 is a transmission-type photo sensor, and
The disk 31 is rotated so that the outer periphery of the groove 31
It is turned on when light passes through a. The position of the groove 31a is related to the direction of the chuck body 11, and is in a direction in which the chuck body 11 does not interfere even when the guide rail 42 is at the position B as shown in FIG. Sometimes, the position is such that it is detected by the sensor 32. The electromagnetic clutch 34 is connected to the rotating shaft 5a by a timing belt 33, and detects the rotation of the motor 5.
During rotation, the clutch is in a disengaged state, and is engaged when the rotation stops. The pulse motor 35 starts driving when the electromagnetic clutch 34 is engaged, and the electromagnetic clutch 34 and the timing belt
Via 33, the chuck main body 11 is rotated until the sensor 32 detects the groove 31a.

The control operation of the stop position in the third embodiment having such a configuration will be described. The semiconductor wafer 11 mounted on the guide rail 42 at the position B is transported to a position on the upper surface of the chuck body 11. At this stage, the processing container 3 does not interfere with the guide rail 42,
It is located below. The chuck body 11 is stopped in a direction that does not interfere with the guide rail 42 as shown in FIG.

The guide rail 42 descends, and the chuck claws 12a, 12b
The semiconductor wafer 1 is guided to the position of the concave portion, and is held in the same manner as in the first embodiment. After the guide rail 42 moves to the position B, the processing container 3 moves upward to the position shown in FIG. When the motor 5 rotates and the removal of water droplets from the surface of the semiconductor wafer 1 is completed, the rotation is stopped. The electromagnetic clutch 34 that detects this stop is connected,
The pulse motor 35 starts rotating. The pulse motor 35 is linked to the sensor 32, and stops rotating when the sensor 32 detects the groove 31a of the disk 31. This allows the chuck body 11
Stops in a direction that does not interfere even when the guide rail 42 is at the position B. Here, the stop position of the chuck body 11 is controlled by using the pulse motor 35 without directly controlling the rotation of the motor 5 because a normal drive motor is required to stop accurately at a fixed position after rotation. Is difficult.

Thereafter, the processing container 3 moves downward. Guide rail
After the position 42 moves from the position A to the position B, the semiconductor wafer 1 is lifted, and the semiconductor wafer 1 is mounted and transported to a predetermined place.

As described above, according to the second embodiment, by controlling the stop position of the chuck main body 11, it is possible to prevent interference with the guide rail.

The above-described embodiments are merely examples, and do not limit the present invention. For example, in both the first and second embodiments, the release of the semiconductor wafer is performed by sending compressed air to the air cylinder. However, it is not always necessary to adopt such a configuration. May be operated so as to be opened. Further, although a spring is used as the elastic body, it may be made of rubber or the like. The counterweight has the effect of preventing the chuck pawl from opening due to centrifugal force, but may not be the case where the weight of the chuck pawl is light or the pressing force of the elastic body is high. Although each of the embodiments has two chuck claws,
It may have three or more.

In the second embodiment, the stop position of the chuck body is controlled in order to avoid interference between the chuck body and the guide rail of the transfer mechanism. However, the interference is not limited to the transfer mechanism and other peripheral devices. It may be something to avoid. Such a stop position control unit does not necessarily have to be provided. This is not necessary if there is no risk that the chuck body will interfere with the transport mechanism regardless of the position of the chuck body depending on the shape of the chuck body or the structure of the transport mechanism.

[Effects of the Invention] As described above, the present invention holds the wafer by supporting the outer edge of the wafer with the chuck claws while the semiconductor wafer is separated from the surface of the chuck main body and pressing the chuck claws with the elastic body. Therefore, the wafer can be reliably held by mechanical elasticity, and since only the outer edge of the wafer comes into contact, water droplets on both surfaces of the wafer can be removed.

In addition, by sending compressed air into the cylinder, the chuck claws move outward in the radial direction, and the holding of the wafer can be easily released, thereby improving workability.

When the chuck pawl has a counterweight, the centrifugal force generated by the counterweight during rotation cancels the centrifugal force generated by the chuck pawl, so that the chuck pawl does not open outward and the wafer is prevented from falling off.

Furthermore, when the stop position of the chuck body is controlled by the stop position control unit, the chuck body stops so as to face a fixed direction, so that interference with other components such as a transport mechanism is avoided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of the first embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, FIG. 3 is a sectional view showing the structure of the second embodiment of the present invention, FIG. 4 is a plan view of FIG. 3, FIG. 5 is a cross-sectional view showing a configuration of a conventional semiconductor wafer supporting device,
FIG. 6 is a plan view of FIG. DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer, 3 ... Processing container, 4 ... Vacuum tube, 5 ... Motor, 11 ... Chuck body, 12a, 12b
… Chuck jaws, 13a, 13b, 13c, 13d …… Counter weights, 14a, 14b …… Air cylinders, 15a, 15b …… Compression springs,
16 ... air passage, 17 ... mounting bracket, 18 ... desk, 19 ...
... air seals, 21a, 21b ... pistons, 31 ... discs, 32
…… Sensor, 33… Timing belt, 34… Electromagnetic clutch, 35… Pulse motor.

Claims (3)

(57) [Claims] 1. A chuck body having at least two air cylinders radially opposed to each other, inserted into said air cylinders, respectively.
A piston that moves in the radial direction, an elastic body that presses the piston inward in the radial direction, a chuck claw fixed to the piston protruding from the chuck body, and a piston that moves the piston radially inside the air cylinder. A compressor that feeds compressed air that presses the chuck body, and a chuck body support that supports the chuck body so that it can rotate, so that the semiconductor wafer is held at a position away from the chuck body surface, A semiconductor wafer holding device, wherein concave portions for supporting an outer edge portion of a semiconductor wafer are provided inside chuck jaws, respectively. 2. A chuck according to claim 1, wherein said chuck pawls have counterweights provided on opposite sides of a center of rotation to generate a centrifugal force having a direction different from a centrifugal force generated on said chuck jaws by rotation. 2. The semiconductor wafer holding device according to claim 1. 3. A flat plate that rotates together with the chuck body, a sensor unit provided on a rotation circumference of the flat plate, and configured to detect a predetermined position on the flat plate related to the directionality of the chuck body, and the sensor. By rotating and stopping the chuck body until the unit detects the location,
3. The semiconductor wafer holding device according to claim 1, further comprising a stop position control unit that stops the chuck body in a predetermined direction.