JP2720166B2 - Wafer support device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer support device that holds and rotates a semiconductor wafer and enables eccentric rotation of a wafer holding member.

[Conventional technology]

Conventionally, in an ion implantation apparatus that performs ion implantation on a wafer, a wafer to be ion-implanted is fixed to a platen, and the wafer is rotated on a plane, so that an ion implantation angle with respect to the wafer is changed, and one wafer is implanted with respect to the wafer. A plurality of times at different angles.

Regarding such ion implantation, in the case of a platen without a rotation mechanism, after performing one ion implantation, the wafer is once taken out of the chamber from the platen, the wafer is rotated at an arbitrary angle, and then the inside of the chamber is again rotated. The procedure of returning to the platen and performing ion implantation is repeated. In the process of changing the angle of the wafer, since a transfer operation is involved, an error is likely to occur between the set angle and the angle at which the ions are actually implanted, and furthermore, since the transfer is performed several times for one wafer, There is a drawback that the possibility that dust adheres to the wafer is increased, and the processing time for one wafer is increased, so that the number of processed wafers (throughput) within a certain time is small.

For this reason, conventionally, a platen provided with a rotation mechanism has been used, and two of the topmost rotating bumpers arranged in a horseshoe or V-shape for holding a wafer are located at the lowest point. Direction, rub the edge of the wafer, and rotate the wafer.

[Problems to be solved by the invention]

By the way, those equipped with the conventional rotating mechanism rotate the wafer by rolling friction, so there is a possibility that the wafer may slip during rotation, and it is not reliable whether the wafer is set at the set angle, and the wafer is not reliable. Is directly rubbed by the drive wheels, and during the rotation, the back surface of the wafer is in contact with the platen and is rubbed, so that dust is likely to be generated, and since the wafer is not in close contact with the platen, the cooling capacity of the wafer is reduced. There were drawbacks such as inferiority.

For this reason, the inventor has proposed a wafer supporting device of Japanese Patent Application No. 62-25236 which integrates holding and rotation of a wafer to perform ion implantation by setting a highly accurate angle.

By the way, in such a wafer support device, when the rotation center of the holding portion for holding the wafer on the mounting portion is eccentric with respect to the rotation center of the mounting portion on which the wafer is mounted, When the mounting portion rotates, a force associated with the rotation acts between the wafer and the holding portion, causing friction with the wafer, which may cause damage to the wafer.

Accordingly, it is an object of the present invention to prevent the holding portion and the wafer from rubbing with the rotation of the holding portion that is eccentric.

[Means for solving the problem]

As illustrated in FIGS. 1 and 2, the wafer support device of the present invention has a mounting portion (platen cup 6) on which a wafer (4) is mounted and rotates, and is mounted on the mounting portion. A first holding member (clamp ring) for holding the wafer on the mounting portion, and a second holding member attached to the outside of the first holding member via a bearing (40). (Outer clamp 42) and a fixing member (clamp block 4) for fixing the second holding member.
And an eccentric rotation mechanism (46) provided between the fourth holding member and the second holding member and configured to eccentrically rotate the second holding member with respect to the center of the mounting portion. And

Further, in the wafer support device of the present invention, the eccentric rotation mechanism (46) is provided between the fixed member and the second holding member, and is capable of moving the second holding member in a horizontal direction. And a linear bearing (linear bearing pair 48) for supporting the linear bearing.

[Action]

According to such a configuration, a bearing (40) is provided on the outside of the first holding member (clamp ring 38) corresponding to the rotation center of the wafer 4 mounted and held on the mounting portion (platen cup 6). The second holding member (outer clamp 42) attached via the interposition can be eccentrically rotated, and the wafer 4 can be securely held and the friction with the holding portion is prevented.

In the wafer support device of the present invention, the eccentric rotation mechanism (46) is provided between the fixing member and the second holding member so as to move the second holding member in the horizontal direction. By providing a supporting linear bearing (linear bearing pair 48), smooth eccentric rotation is possible,
The wafer can be protected from scratches caused by friction.

〔Example〕

1 to 5 show an embodiment of the wafer support device of the present invention.

As shown in FIG. 1 and FIG. 2, a bellows 8 is installed on the lower surface of the platen main body 2 forming the base of the platen mechanism, as a lifting / lowering means for lifting / lowering a platen cup 6 as a mounting portion of the wafer 4. A cup holder 10 is attached to the upper part of the cup 8. A pressure fluid 16 flows into a space inside the bellows 8 from a fluid hole 14 provided at the center of the bellows plate 12 of the bellows 8, thereby promoting the expansion of the bellows 8, and a cup holder placed thereon.
10 can be raised vertically. Cup holder 10
Is vertically balanced so as to vertically penetrate the platen body 2 and is elastically balanced by a guide shaft 20 to which a spring 18 biasing the platen body 2 is attached. The guide shaft 20 is disposed radially around the center axis of the cup holder 10 at a constant angle and is slidable through the platen body 2. The spring 18 is inserted between the lower surface of the platen body 2 and the receiving portion 22 attached to the guide shaft 20, and elastically holds the cup holder 10.

The platen cup 6 is rotatably mounted on the upper surface of the cup holder 10 via the bearing 34 together with the inner race 32.
Is attached. A gear 24 is formed on the inner periphery of the platen cup 6, and the gear 24 has a motor 26
The gear 30 attached to the rotary shaft 28 is meshed. Further, the platen cup 6 has a circular shape, and has a concave portion 36 for mounting the wafer 4 thereon.

Above the platen cup 6, a circular clamp ring 38 is provided as a first holding member for holding the placed wafer 4 on the platen cup 6 raised by the extension of the bellows 8. This clamp ring 38
Is rotatably attached to an outer clamp 42 as a second holding member via a bearing 40. That is, when the platen cup 6 pushed up by the bellows 8 rotates through the gears 30 and 24, the clamp ring 38 also rotates through the held wafer 4.

Above the outer clamp 42, the outer clamp 42
In addition, a clamp block 44 as a fixing member is installed, and an eccentric rotation mechanism 46 for eccentrically rotating the outer clamp 42 is attached to the clamp block 44.

The eccentric rotation mechanism 46 includes, for example, four linear bearing pairs 48 with the outer clamp 42 and the clamp block 44.
The outer clamp 42 and the clamp block are provided as shown in FIGS. 3 and 4.
The recessed portions 50 and 52 are provided in the facing surface portion of 44, and X,
Four linear bearing pairs 48 that slide and move in the Y-axis direction are installed and fixed with bolts 54 and 56.

Each linear bearing pair 48 is, as shown in FIG.
Linear bearing 48 that moves in one direction of the X and Y axes
A and 48B are moved perpendicular to each other, and brackets 58 and 60
It is what was unified with. In this case, the bracket 58 is attached to the linear bearing 48A with the screw 62, the bracket 60 is attached to the linear bearing 48B with the screw 64, and the brackets 58 and 60 are connected with the screws 66 and 68, so that Bearings 48A and 48B are integrated.

And each linear bearing 48A, 48B is a rail 70
The rail portion 70 is fixed to each other with brackets 58 and 60, and the sliding shaft portion 72 is mounted to the outer clamp 42 or the clamp block 44 by bolts 54 and 56.

In such a configuration, after placing the wafer 4 on the platen cup 6, the pressure fluid 16 is placed inside the bellows 8.
To extend the bellows 8, the cup holder 10 and the platen cup 6 rise. At this time, the guide shaft 20 is also pulled up, and the receiving portion 22 fixed on the upper portion of the guide shaft 20 and the platen body 2
The spring 18 inserted between them is compressed. The guide shaft 20 can smoothly move up and down through the platen body 2, and functions as a guide when moving up and down the cup holder 10 and the platen cup 6.
As a result, the wafer 4 is sandwiched between the platen cup 6 and the clamp ring 38 as shown in FIG. When the wafer 4 is removed, the reaction force of the compressed spring 18 acts by lowering the pressure of the pressurized fluid 16 in the bellows 8 to lower the cup holder 10 and fix the platen cup 6 fixed thereto. The unclamping is completed by lowering.

Then, a gear 30 formed on an inner peripheral portion of the platen cup 6 is meshed with a gear 30 attached to a rotating shaft 28 of a motor 26. When the motor 26 is rotated, the wafer 4 rotates together with the platen cup 6, At this time, the clamp ring 38 also rotates.

As shown in FIG. 6, when the rotation center O of the platen cup 6 and the rotation center O 'of the clamp ring 38 do not coincide with each other, for example, by rotating the clamp ring 38 in the directions of arrows a and b, The rotation center O 'generates a circular motion as shown by an arrow c due to the eccentric rotation of the eccentric rotation mechanism 46. That is, the eccentric rotation mechanism 46 is
The clamp ring 38 has four movable bearing pairs 48 slidable in the axial direction. The clamp ring 38 has a movable range indicated by d in FIGS. 7A and 7B. Thus, the rotation center O 'can perform a circular motion.
Therefore, if the rotation center O of the platen cup 6 does not match the rotation center O 'of the clamp ring 38, the eighth
As shown in the figure, the outer clamp 42 holding the clamp ring 38 exhibits a parallel parallel motion in a circle, and as a result, the clamp ring 38 produces a smooth circular motion in response to the rotation of the platen cup 6, so that the Friction can be prevented.

By using the pair of nilia bearings 48 as described above, the clamp ring 38 for holding the wafer 4 on the platen cup 6 can be used.
The smooth eccentric rotation can be performed with a simple configuration without impairing the function of (1).

In the embodiment, the example using the linear bearing pair 48 as the eccentric rotation mechanism 46 has been described. However, the eccentric rotation mechanism 46 may use spring means for performing eccentric rotation.

〔The invention's effect〕

As described above, according to the present invention, a bearing is interposed outside the first holding member for holding the wafer on the mounting portion with respect to the rotation center of the mounting portion on which the wafer is mounted. When the rotation center of the attached second holding member is eccentric, the holding portion is eccentrically rotated by the eccentric rotation mechanism according to the eccentricity, so that the wafer is securely fixed on the mounting portion. In addition to this, it is possible to prevent the wafer from being damaged by friction without causing friction with the wafer.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view showing an embodiment of the wafer support device of the present invention, FIG. 2 is a central longitudinal sectional view of the wafer support device shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is an exploded perspective view showing an eccentric rotation mechanism of the wafer support device, and FIG.
FIG. 5 is a partially cutaway side view showing an eccentric rotation mechanism of the wafer support device shown in FIG. 5, FIG. 5 is an exploded perspective view showing a linear bearing pair of the eccentric rotation mechanism in the wafer support device shown in FIG. FIG. 8 to FIG. 8 are diagrams showing the eccentric rotation operation of the clamp ring. 4 wafer 6 platen cup (mounting part) 38 clamp ring (first holding member) 40 bearing 42 outer clamp (second holding member) 44 clamp block (fixing member) 46 …… Eccentric rotation mechanism 48 …… Linear bearing pair

Claims (2)

(57) [Claims] A first mounting member for mounting and rotating a wafer, a first holding member for holding the wafer mounted on the mounting portion and holding the wafer on the mounting portion; A second holding member attached to the outside of the holding member through a bearing, and a mounting member provided between the fixing member for fixing the second holding member and the second holding member. An eccentric rotation mechanism configured to eccentrically rotate the second holding member with respect to a center. 2. The eccentric rotation mechanism includes a linear bearing provided between the fixed member and the second holding member to support the second holding member movably in a horizontal direction. The wafer support device according to claim 1.