JPH0736416B2 - Wafer transfer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer apparatus that transfers a wafer between two locations in an implantation chamber of an ion implantation apparatus in upper and lower two stages in mutually opposite directions.

[Background technology]

When loading and unloading (loading and unloading) wafers between the implantation chamber of the ion implantation system and the atmosphere side, normally two vacuum reserve chambers (for loading and unloading) are required, but that is Since the structure is complicated and the device becomes large, an ion implantation device with a single vacuum reserve chamber was devised.

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

A vacuum preliminary chamber for loading / unloading the wafer 4 between the inside of the implantation chamber 6 and the atmosphere side is provided at the bottom of the implantation chamber 6 at the rear side.
20 are adjacent to each other.

The details of the vacuum reserve chamber 20 are shown in FIG. That is,
A vacuum reserve 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 separates from the injection chamber 6 is provided at the upper part, and a vacuum side valve 28 is provided at the lower part to connect to the atmosphere side. Atmosphere-side valves 30 for partitioning the spaces are provided respectively.

The vacuum side valve 28 is opened and closed by an air cylinder 26 provided on the injection chamber 6, and the atmosphere side valve 30 is opened and closed by a lower air cylinder 42 via a guide shaft 38. It should be noted that the lever 24 and the air cylinder provided above the air cylinder 26
Reference numeral 22 is for locking the air cylinder 26.

A rotary table 34 on which the wafer 4 is placed is provided above the atmosphere side valve 30. The rotary table 34 is rotated by a motor 36 for alignment flat alignment of the wafer 4 and the like, and a dual stroke cylinder is also provided.
The wafer 40 is moved up and down in two steps for handling the wafer 4.

The transfer of the wafer 4 between the vacuum preliminary chamber 20 and the holder 7 is performed in two steps, that is, the wafer transfer device for that purpose has the following structure.

That is, a ball screw 14a and a guide shaft 16 are arranged along the transfer path of the wafer 4 in the injection chamber 6 as a load side, and a transfer arm 12a on which the wafer 4 can be mounted is attached to the ball screw 14a. By rotating the motor 18a outside the injection chamber 6 in both forward and reverse directions, the transfer arm
12a is moved linearly.

Further, as the unload side, below the function of the load side as described above, with the same configuration as that, the transfer arm 12b,
A ball screw 14b, a guide shaft 16b and a motor 18b are provided (all are not shown in FIG. 4 because they are on the lower side).

Then, the unimplanted wafer 4 is transferred to the vacuum preliminary chamber 20 from the atmosphere side.
Transfer arm into the injection chamber 6 via the
In parallel with mounting the holder 7 in the horizontal state by 12a, the wafer 4 having been implanted is received from the holder 7 in the horizontal state by the transfer arm 12b on the unload side, and is transferred to the atmosphere via the vacuum preliminary chamber 20. I try to put it out to the side.

[Problems to be Solved by the Invention]

However, in the wafer transfer device as described above, two sets of dedicated mechanisms are used on the loading side and the unloading side, respectively, and therefore there is a problem that the structure becomes complicated and the cost becomes high.

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

[Means for Solving the Problems] In order to achieve the above object, the wafer transfer apparatus of the present invention is a timing belt suspended along a transfer path of a wafer, and an upper portion and a lower portion of the timing belt. Two transfer arms mounted on the respective parts and capable of mounting a wafer, guide means for guiding each of the transfer arms to move along the timing belt without rotating, and the timing belt in both forward and reverse directions. And a motor that is driven to rotate.

[Action]

When the motor is rotated in a predetermined direction, the timing belt is driven, whereby the two transfer arms move in opposite directions while being guided by the guide means. This allows the wafer loading and unloading transfer to be performed simultaneously.

〔Example〕

FIG. 1 is a horizontal sectional view partially showing an example of an ion implantation apparatus including a wafer transfer apparatus according to an embodiment of the present invention. The same or corresponding parts as those in the example of FIG. 4 are designated by the same reference numerals, and the difference from them will be mainly described below.

This ion implanter is an example of a so-called hybrid scan system in which an ion beam 2 is electrically scanned so as to be a parallel beam in a horizontal direction, and a holder 7 having a wafer 4 is mechanically vertically scanned. (still,
The same mechanism as on the right side is also provided on the left side of the figure, but it is dualized, but this is not essential, so its explanation is omitted here).

That is, a holder 7 is provided in the implantation chamber 6 into which the ion beam 2 formed into a parallel beam is introduced. The holder 7 is described later in detail by a holder driving device 70.
It is moved between a standing state shown by a solid line in FIG. 1 and a horizontal state shown by a two-dot chain line.

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

A wafer transfer device 50 having the following structure is provided in a portion from the vacuum preliminary chamber 20 to the holder 7 in the horizontal state.

That is, referring also to FIG. 2, one timing belt is provided between the two grooved pulleys 60 and 62 along the transfer path of the wafer 4 between the vacuum preliminary chamber 20 and the holder 7 in the horizontal state. 58 are looped around. A motor 64 capable of normal rotation and reverse rotation is connected to one pulley 60. The above-described load side transfer arm 12a and unload side transfer arm 12b are attached to the upper and lower portions of the timing belt 58 via connecting fittings 56, respectively.

Further, a ball spline is adopted in this embodiment as a guide means for guiding the transfer arms 12a and 12b to move along the timing belt 58 without rotating.
That is, spline bearings are provided at the roots of the transfer arms 12a and 12b.
54a and 54b are attached, and upper and lower two spline shafts 52a and 52b penetrating them are arranged in parallel to the timing belt 58.

If such a ball spline is adopted, the single spline shaft can guide the transport arm to travel horizontally and stably without rotating.

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

An operation example of wafer transfer by the wafer transfer device 50 will be described.

The holder driving device 70 moves the holder 7 to the position shown by the chain double-dashed line in FIG. The arm 12b is raised to a position where it is handed over.

On the other hand, on the side of the vacuum reserve chamber 20, referring to FIG. 3, both the upper and lower cylinders of the dual stroke cylinder 40 are operated to raise the rotary table 34 greatly, and as shown by the chain double-dashed line, The uninjected wafer 4 is lifted up to the position of the transfer arm 12a, and in that state, the timing belt 58 is driven by the motor 64 of the wafer transfer device 50 to bring the transfer arm 12a to the position on the vacuum preliminary chamber 20 and the transfer arm 1
2b is moved to a position on the holder 7 at the same time, and the wafer receiver 8 of the holder 7 is lowered so that the wafer 4 which has already been implanted is placed on the transfer arm 12b. Unimplanted wafer 4 is transferred to arm 12
Put it on a.

Next, the motor 64 of the wafer transfer device 50 is reversed from the previous one, and the transfer arm 12b on which the implanted wafer 4 is placed is placed on the vacuum auxiliary chamber 20 and the transfer arm 12b on which the unimplanted wafer 4 is placed.
12a is moved onto the holder 7, and only the upper cylinder of the dual stroke cylinder 40 is operated on the side of the vacuum reserve chamber 20 to receive the wafer 4 from the transfer arm 12b by the rotary table 34 (the solid line in FIG. 3). ), Holder 7
On the side, the wafer 4 is received by the wafer receiver 8 from the transfer arm 12a.

Next, the motor 64 of the wafer transfer device 50 is rotated in the reverse direction again to move both transfer arms 12a and 12b to the intermediate standby position (the state shown in FIG. 1), and the holder 7 side receives the wafer receiver 8a.
Then, the wafer retainer 9 is lowered to hold the wafer 4, and the holder driving device 70 moves the holder 7 to the implantation state shown by the solid line in FIG. 1 to complete the implantation preparation.

On the other hand, in the vacuum reserve chamber 20, after the rotary table 34 is lowered and the vacuum side valve 28 is closed, the inside of the vacuum reserve chamber 20 is returned to the atmospheric pressure state and the atmosphere side valve 30 is opened (this state is the fifth level). (See the figure),
The unillustrated wafer 4 is carried out and the next unimplanted wafer 4 is carried in by an atmosphere side transfer arm device (not shown). At this time, in the implantation chamber 6, the wafer 4 on the holder 7 is irradiated with the ion beam 2 to perform ion implantation.

After that, the same operation as described above is repeated as necessary.

As described above, in this wafer transfer apparatus 50, the load side transfer arm 12a and the unload side transfer arm 12b are attached to the one timing belt 58 in the two upper and lower stages, and the timing belt 58 is normally and reversely rotated by the one motor 64. Since it is configured to rotate in both directions, the structure is simpler and the cost is lower than that of the wafer transfer apparatus described in FIG. This is because the ball screw is more expensive than the timing belt, but in the above example, two such ball screws are used and two motors are also used. This is because the timing belt 54, which is less expensive than the ball screw, is used, and only one of the timing belt 54 and the motor 64 is required.

In addition, it is preferable to use the ball spline as described above as the guide means of the transfer arms 12a and 12b from the viewpoint of simplification of the structure, but it is also possible to use two normal guide shafts instead. is there.

Next, the holder driving device 70 will be described. A vacuum seal bearing 72 is attached to the side wall of the injection chamber 6, a support shaft 74 is penetrated through it, and a gear 76 is attached to the atmosphere side (outside of the injection chamber 6) of the injection angle. The support shaft 74 is rotated as shown by arrow A by the variable motor 80 and the gear 78, and the arm 10
The holder 7 attached via 6 is driven to a preset implantation angle position and a horizontal position for handling the wafer 4.

The arm shaft 100 and the arm 106 are rotatably supported by a vacuum seal bearing 98 on the vacuum side (inside the injection chamber 6) of the support shaft 74. A pulley 96 is attached to one end of the arm shaft 100, and a supporting shaft 94 is attached by a timing belt 92.
It is connected to the scanning motor 84 and pulley 88 mounted on the atmospheric side of the arm 10 by this motor 84.
6 is rotated in the direction of arrow B so that the holder 7 is scanned in the vertical direction (front and back of the paper).

Attach a vacuum seal bearing 112 to the tip of the arm 106,
The holder shaft 114 and the holder 7 are rotatably supported.
A pulley 110 is attached to the holder shaft 114. 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 thereof.

The pulleys 104 and 110 have the same diameter and are connected by a timing belt 108. Further, a step rotation motor 82 attached to the atmosphere side of the support shaft 74 and a pulley 86 and a pulley 94 are connected by a timing belt 90. The motor 82 causes the holder 7 to be stepwise as shown by an arrow C, for example. It can be rotated (however, rotation during injection is not performed).

A chain may be used instead of the timing belts 90, 92 and 108, and in that case, the pulley associated therewith may be a chain gear.

To describe the posture of the holder 7 during scanning, the motor 82 is stopped during scanning, and therefore the intermediate shaft 102 and the pulley 104 are stopped. In this state, the motor 84 is operated by the pulley 88, the timing belt 92 and the pulley 96.
When the arm 106 is rotated by θ ° in the clockwise direction via, the pulley 104 is rotated by θ ° in the counterclockwise direction when viewed from the arm 106 side, which is the same as the pulley 104 connected by the timing belt 108. The diameter pulley 110 rotates counterclockwise θ ° when viewed from the arm 106 side. Therefore, the holder 7 draws a circular arc in the vertical direction with the length of the arm 106 as a radius, but its absolute rotation angle is 0 ° and its posture is unchanged, and this and the ion beam 2 are made into a parallel beam in the horizontal direction. In combination with this, the wafer 4 on the holder 7 can be uniformly ion-implanted.

In order to move the holder 7 to the wafer 4 handling position shown by the chain double-dashed line in FIG. 1, the motor 7 should bring the holder 7 into a horizontal state and the motor 84 should move the holder 7 to the wall side. By doing so, the holder 7 consequently moves as shown by the arrow D.

However, the holder driving device is not necessarily limited to the above-mentioned one, and various ones can be adopted depending on the scanning method of the ion beam 2 and the like including the one described in FIG. .

〔The invention's effect〕

As described above, according to the present invention, the loading arms and the unloading side transport arms are vertically arranged on one timing belt.
Since it is attached to the stage, and this timing belt is configured to be rotationally driven in both forward and reverse directions by one motor,
The structure is simple and the cost is low.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view partially showing an example of an ion implantation apparatus including a wafer transfer apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing the wafer transfer device in FIG. FIG. 3 is a cross-sectional view taken along line I-I of FIG. 1, showing a state in which the vacuum side valve is opened and the atmosphere side valve is closed. FIG. 4 is a horizontal sectional view partially showing an example of the ion implantation apparatus which is the background of the present invention. Figure 5 shows
FIG. 2 is a sectional view taken along the line II-II in FIG. 4, showing a state in which the vacuum side valve is closed and the atmosphere side valve is opened. 2 ... Ion beam, 4 ... Wafer, 6 ... Implantation chamber,
7 ... Holder, 12a, 12b ... Transfer arm, 20 ... Vacuum pre-chamber, 50 ... Wafer transfer device, 52a, 52b ... Spline shaft, 54a, 54b ... Spline bearing, 58 ... Timing belt, 60 ……motor.

Claims (1)

[Claims] 1. An apparatus for transporting a wafer between two locations in an implantation chamber of an ion implantation apparatus in upper and lower two steps in opposite directions to each other, and a timing belt suspended along a transportation path of a wafer and a timing belt of the timing belt. Two transfer arms mounted on the upper part and the lower part, respectively, on which a wafer can be placed, and guide means for guiding each of the transfer arms to move along the timing belt without rotating. And a motor that drives the timing belt to rotate in both forward and reverse directions.