JPH02196441A - Wafer conveying apparatus - Google Patents

Abstract

PURPOSE:To obtain a low cost apparatus of simple structure used in an ion implantation system, by fixing conveying arms to the upper stage and the lower stage of a timing belt, and rotating the timing belt in the forward and the backward directions, by a motor. CONSTITUTION:A conveying apparatus carries wafers between two places in an implantation chamber of ion implantation system, in the manner in which carriage is divided into the upper stage and the lower stage having opposite directions. A timing belt 58 is suspended along the wafer conveying route. Conveying arms 12a, 12b are installed on the upper side part and the lower side part of the timing belt 58, respectively, and can mount the wafers. Guiding means 52a, 52b, 54a, 54b guide the conveying arms 12a, 12b which move along the timing belt 58 without rotating. A motor 64 drives the timing belt so as to rotate it in the forward direction and the backward direction. For example, the guide means is constituted of spline bearings 54a, 54b and two spline sfafts 52a, 52b of the upper one and the lower one penetrating the respective bearings.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wafer transport device that transports wafers in two stages, upper and lower, in opposite directions between two locations within an implantation chamber of an ion implantation apparatus.

[Background technology]

When wafers are transferred (loaded and unloaded) between the implantation chamber and the atmosphere side of an ion implanter, two vacuum preliminary chambers (one for loading and one for unloading) are usually required. Because of the complicated structure and large size of the device, we devised an ion implantation device with a single vacuum preliminary chamber.

To explain such an ion implantation apparatus with reference to FIG. 4, a holder capable of holding a wafer 4 is placed in an implantation chamber 6, which is a chamber evacuated by a vacuum pump (not shown) and into which the ion beam 2 is introduced. 7 is provided, and this holder 7 is rotated by a holder driving device 10 between a horizontal state as shown in the figure and an upright state for obtaining a predetermined injection angle.

Adjacent to the bottom of the rear portion of the injection chamber 6 is a vacuum preliminary chamber 20 for transferring the wafer 4 between the injection chamber 6 and the atmosphere side.

The details of this vacuum preliminary chamber 20 are shown in FIG. That is, a vacuum preliminary chamber 20 that is evacuated by a vacuum pump 32 is provided at the bottom of the injection chamber 6, a vacuum side valve 28 that partitions off the injection chamber 6 from the injection chamber 6 at the top, and a vacuum side valve 28 at the bottom that separates the chamber from the atmosphere side. Atmospheric side valves 30 are respectively provided to partition between the two.

The vacuum side valve 28 and the atmosphere side valve 30 are raised and lowered and opened and closed by an air cylinder 26 provided above the injection chamber 6 and a lower air cylinder 42 via a guide shaft 38, respectively. Note that the lever 24 and the air cylinder 22 provided at the top of the air cylinder 26 are for locking the air cylinder 26.

Above the atmosphere side valve 30, there is a rotary table 3 on which the wafer 4 is placed.
4 is provided, and this rotary table 34 is rotated by a motor 36 for aligning the orientation of the wafer 4 flat, etc., and is raised and lowered in two stages by a dual stroke cylinder 40 for handling the wafer 4, etc. .

The wafer 4 is transferred between the vacuum preparatory chamber 20 and the holder 7 in two stages, upper and lower, and the wafer transfer device for this purpose usually has the following structure.

That is, a ball screw 14a and a guide shaft 16a are installed in the injection chamber 6 on the load side along the transport path of the wafer 4.
A transfer arm 1 on which a wafer 4 can be placed
2a is attached, and this ball screw 14a is rotated in both forward and reverse directions by a motor 18a outside the injection chamber 6, thereby moving the transfer arm 12a linearly.

Further, as an unloading side, a transport arm 12b with exactly the same configuration is installed below the loading side mechanism as described above.
1 ball screw 14b, guide shaft 16b and motor 18
b (both are located on the lower side in Figure 4 and are not shown in the figure).

Then, the unimplanted wafer 4 is transferred from the atmosphere side to the vacuum preliminary chamber 2.
The implanted wafer 4 is placed into the implantation chamber 6 via the loading side transfer arm 12a and placed on the horizontal holder 7 by the unloading transfer arm 12b. The receiver is taken from the holder 7 in the current state and is delivered to the atmosphere via the vacuum preliminary chamber 20.

[Problem to be solved by the invention]

However, the above-described wafer transfer apparatus uses two sets of dedicated mechanisms on the load side and the unload side, respectively, resulting in a problem that the structure is complicated and the cost is also high.

Therefore, the main object of the present invention is to provide a wafer transfer device that is used in, for example, the above-mentioned ion implantation device, and has a simple structure and is inexpensive.

[Means to solve the problem]

In order to achieve the above object, the wafer transport device of the present invention includes a timing belt that is suspended along the wafer transport path, and a timing belt that is attached to the upper and lower parts of the timing belt to transport the wafer. Two transport arms that can be placed, guide means that guide each transport arm to move along the timing belt without rotating, and a motor that rotates the timing belt in both forward and reverse directions. It is characterized by

[Effect]

When the motor is rotated in a predetermined direction, the timing belt is driven, whereby the two transport arms are guided by the guide means and move in opposite directions. This allows simultaneous loading and unloading of the wafer.

〔Example〕

FIG. 1 is a horizontal sectional view partially showing an example of an ion implantation apparatus equipped with a wafer transfer device according to an embodiment of the present invention. The same reference numerals are given to the same or corresponding parts as in the example of FIG. 4, and the differences therefrom will be mainly explained below.

This ion implantation apparatus is an example of a so-called hybrid scanning system in which the ion beam 2 is electrically scanned horizontally to form a parallel beam, and the holder 7 on which the wafer 4 is mounted is mechanically scanned up and down. (still,
The left side of the figure has the same mechanism as the right side, making it dual, but since this is not essential, its explanation will be omitted here.)

That is, a holder 7 is provided in the implantation chamber 6 into which the collimated ion beam 2 is introduced, and this holder 7 is moved by a solid line in FIG. It can be moved between an upright state as shown by and a horizontal state as shown by a two-dot chain line.

Adjacent to the bottom of the rear portion of the injection chamber 6 is the vacuum preliminary chamber 20 as described above.

A wafer transfer device 5 having the following structure is installed between the vacuum preliminary chamber 20 and the horizontal holder 7.
0 is set.

That is, referring also to FIG. 2, along the transport path of the wafer 4 between the vacuum preliminary chamber 20 and the holder 7 in a horizontal state,
A timing belt 58 is looped between two grooved pulleys 60 and 62. One pulley 60 has a motor 6 that can rotate forward and reverse.
4 are connected. And this timing belt 5
Connecting fittings 56 are provided on the upper and lower parts of 8, respectively.
The load-side transport arm 12a as described above
and an unloading side transport arm 12b are respectively attached.

Further, in this embodiment, a ball spline is used as a guide means for guiding each conveyance arm 12a, 12b to move along the timing belt 58 without rotating. That is, spline bearings 54a and 54b are attached to the base of each transport arm 12aS 12b, and two upper and lower spline shafts 5 passing through them respectively.
2a and 52b are arranged parallel to the timing belt 58.

If such a ball spline is employed, one spline shaft can guide the transport arm so that it runs stably horizontally without rotating.

Although each of the spline shafts 52a and 52b is shown as a round bar for simplification, in reality, it is a round bar or of an irregular shape having a plurality of ball transfer grooves.

An example of the operation of wafer transport by such a wafer transport device 50 will be described.

The holder 7 is moved by the holder drive device 70 to the position shown by the two-dot chain line in FIG. The arm 12b is raised to the position where it is to be transferred.

On the other hand, on the vacuum preliminary chamber 20 side, referring to FIG. 3, both the upper and lower cylinders of the dual stroke cylinder 40 are operated to greatly raise the rotary table 34, and as shown by the two-dot chain line, the upper load side The uninjected wafer 4 is lifted up to the position of the transfer arm 12a, and in this state, the timing belt 58 is driven by the motor 64 of the wafer transfer device 50 to move the transfer arm 12a to a position above the vacuum preliminary chamber 20 and the transfer arm 12b. are simultaneously moved to a position above the holder 7, and the wafer receiver 8 of the holder 7 is lowered to first place the wafer 4 for the implantation method on the transfer arm 12b.
On the other hand, also on the vacuum preliminary chamber 20 side, the rotary table 34 is lowered and the unimplanted wafer 4 is placed on the transfer arm 12a.

Next, the motor 64 of the wafer transfer device 50 is reversed, and the transfer arm 12b carrying the implanted wafer 4 is moved onto the vacuum preliminary chamber 20, and the transfer arm 12a carrying the uninjected wafer 4 is placed on the vacuum preliminary chamber 20. is moved onto the holder 7, and only the upper cylinder of the dual stroke cylinder 40 is operated on the vacuum preliminary chamber 20 side, and the wafer 4 is received from the transfer arm 12b by the rotary table 34 (as indicated by the solid line in FIG. 3). state), on the holder 7 side, the wafer 4 is received from the transfer arm 12a by the wafer receiver 8.

Next, the motor 64 of the wafer transfer device 50 is reversed again to move the retransfer arms 12a and 12b to the intermediate standby position (the state shown in FIG. 1), and the wafer receiver 8 and wafer presser 9 are lowered on the holder 7 side. The wafer 4 is held by the wafer 4, and the holder 7 is moved by the holder driving device 70 to the implantation state as shown by the solid line in FIG. 1, thereby completing the implantation preparation.

On the other hand, in the vacuum preliminary chamber 20, after lowering the rotary table 34 and closing the vacuum side valve 28, the inside of the vacuum preliminary chamber 20 is returned to the atmospheric pressure state and the atmospheric side valve 30 is opened (this state is the fifth
(see figure), the implanted wafer 4 is carried out and the next unimplanted wafer 4 is carried in by a transport arm device on the atmosphere side (not shown). At this time, in the injection chamber 6, the holder 7
Ion implantation is performed by irradiating the upper wafer 4 with the ion beam 2.

Thereafter, operations similar to those described above are repeated as necessary.

In this way, in this wafer transfer device 50, the load-side transfer arm 12a and the unload-side transfer arm 12b are attached to one timing belt 58 in two stages, upper and lower, and the timing belt 58 is moved forward and backward by one motor 64. Since it is configured to rotate in both directions, the fourth
The structure is simpler and the cost is lower than that of the wafer transfer device described in the figures and the like. This is because ball screws are more expensive than timing belts, but whereas the previous example used two such ball screws and two motors, this wafer transport device 5
0 uses a timing belt 54 that is cheaper than a ball screw.
This is because only one timing belt 54 and one motor 64 are required.

It is preferable to use a ball spline as described above for the guide means of the transport arms 12a and 12b from the viewpoint of simplifying the structure, but it is also possible to use two normal guide shafts instead. be.

Next, to explain the holder drive device 70, a vacuum seal bearing 72 is attached to the side wall of the injection chamber 6, and a support shaft 72 is attached to the side wall of the injection chamber 6.
4 and a gear 76 on the atmosphere side (outside of the injection chamber 6).
Attach the motor 80 and gear 78 for varying the injection angle.
, the support shaft 74 is rotated in the direction of arrow A, and the holder 7 attached to the tip of the support shaft 74 via the arm 106 is driven to the set injection angle position and the horizontal position of the handling stop for the wafer 4. I have to.

On the vacuum side of the support shaft 74 (inside the injection chamber 6), an arm shaft 100 and an arm 106 are rotatably supported by a vacuum sealed bearing 98. A pulley 96 is attached to one end of the arm shaft 100, and is connected by a timing belt 92 to a scanning motor 84 and a pulley $8 attached to the atmospheric side of the support shaft 94. is rotated in the direction of arrow B to scan the holder 7 in the vertical direction (front and back directions of the page).

A vacuum-sealed bearing 112 is attached to the tip of the arm 106 to rotatably support the holder shaft 114 and the holder 7. A pulley 110 is attached to the holder shaft 114. Further, an intermediate shaft 102 is rotatably passed through the center of the arm shaft 100, and pulleys 94 and 104 are attached to both ends of the intermediate shaft 102.

The pulleys 104 and 110 have the same diameter and are connected by a timing belt 108. Further, a step rotation motor 82 and a pulley 86 attached to the atmosphere side of the support shaft 74 are connected to a pulley 94 by a timing belt 90. It is designed so that it can be rotated (however, rotation is not performed during injection).

Incidentally, a chain may be used in place of the timing belts 90, 92 and 108, in which case the associated pulley may be a chain gear.

To explain the attitude of the holder 7 during scanning, the motor 82 is stopped during scanning, and therefore the intermediate shaft 102 and pulley 104 are in a stopped state. In this state, the motor 84 operates the boot IJ-88 and the timing belt 92.
For example, when the arm 106 is rotated by θ° clockwise via the pulley 96, the pulley 104 is rotated θ° counterclockwise when viewed from the arm 106 side, and the pulley 104 connected by the timing belt 108 is rotated by θ°. 110
The pulley 110 having the same diameter as the arm 106 rotates counterclockwise by θ° when viewed from the arm 106 side. Therefore, the holder 7 draws an arc in the vertical direction with the length of the arm 106 as its radius, but the absolute rotation angle is Oo and its posture remains unchanged. Combined with this, ions can be uniformly implanted into the wafer 4 on the holder 7.

In order to move the holder 7 to the wafer 4 handling position shown by the two-dot chain line in FIG. If this is done, the holder 7 will eventually move in the direction of the arrow.

However, the holder driving device is not necessarily limited to the one described above, and various types including the one explained in FIG. 4 can be adopted depending on the method of scanning the ion beam 2, etc. .

〔Effect of the invention〕

As described above, according to the present invention, one timing belt has two upper and lower transport arms on the loading side and the unloading side.
The timing belt is attached to the stage and configured to rotate in both forward and reverse directions with a single motor.
The structure becomes simpler and the cost becomes lower.

[Brief explanation of the drawing]

FIG. 1 is a horizontal sectional view partially showing an example of an ion implantation apparatus equipped with a wafer transfer device according to an embodiment of the present invention. FIG. 2 is a perspective view showing the wafer transfer device in FIG. 1. FIG. 3 is a sectional view taken along line II in FIG. 1, showing a state in which the vacuum side valve is open and the atmosphere side valve is closed. FIG. 4 is a horizontal cross-sectional view partially showing an example of an ion implantation apparatus that is the background of the present invention. Figure 5 shows
FIG. 4 is a sectional view taken along line -H in FIG. 4, showing a state in which the vacuum side valve is closed and the atmosphere side valve is open. 2... Ion beam, 4... Wafer, 6... Injection chamber, 7... Holder, 12a, 12b... Transfer arm, 20... Vacuum preliminary chamber, 50... Wafer transfer device , 52a, 52b... spline shaft, 54a, 54
b...Spline bearing, 5 days/0. Timing belt, 60..., motor. Figure 1

Claims (1)

[Claims] (1) Place the wafer in the implantation chamber of the ion implanter.
In a device that transports wafers between two stages in opposite directions, there is a timing belt that spans along the wafer transport path, and a timing belt that is attached to the upper and lower parts of the timing belt, respectively. two transport arms on which the timing belt can be placed, guide means for guiding each transport arm to move along the timing belt without rotating, and a motor for rotating the timing belt in both forward and reverse directions. A wafer transfer device characterized by: