JPS6232625A - Wafer positioning device - Google Patents

Abstract

PURPOSE:To realize a device capable of exact positioning despite of the irregularity of wafer dimension, and of minimizing the generation of dust and scratches, by installing a movable roller at least, centering means, rotating means, transfer means, and push-traveling means. CONSTITUTION:Regardless of the shape and the size of a wafer 3, its centering is realized by operating an air switching valve 56 and traveling centering chucks 30 and 31 so as to approach with each other. When air switching valve 56 is changed to a neutral position, the spacing between the centering chucks 30-31 is slightly enlarged by the action of return roller 48 energized by a spring. In this state, a rotating stage 7 rotates the wafer 3 while attracting it, and an orientation flat 4 positions it on the side of a sensor 5. Then the pusher 58 is advanced forward in the direction of an arrow 59 to push the orientation flat 4, which is slightly displaced. Thus the position of the wafer 3 is corrected with a little shifting, so that the exact positioning of the wafer 3 is achieved without errors in the right and left directions.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a wafer positioning device, and more particularly to a device suitable for determining the position of an orientation flat of a semiconductor wafer before processing the same.

Conventionally, before a semiconductor wafer (slice) is washed with water, cleaned, etc., an orientation flat positioning device 1 as shown in FIG.
An operation is performed in which the orientation flats 4 are positioned by taking out the individual objects. This work involves positioning the orientation flat 4, examining the lofted fish attached to the same flat position using a combination of the reflective sensor 5 and the image processing camera 6, and checking whether or not the target of the above processing is incorrect. belongs to.

In addition to positioning the wafer accurately, this work requires minimizing scratches and dust on the wafer, but no conventional equipment exists that can meet these demands.

For example, in the apparatus shown in FIG. 11, a wafer slice 3 is supported on a rotation stage 7 having a vacuum chuck structure and rotated in the direction of arrow 8, and when the orientation flat 4 turns on a pair of reflective sensors 5 (i.e. , when the sensor 5 is exposed as shown in the figure), the rotation is stopped and positioning is performed. Then, at this position, the upper camera 6
Due to this, lot I near orientation flat 4
Read two. In addition, in the figure, 9 is a vacuum suction groove of the rotation stage 7, 10 is a vacuum suction pipe connected to the rotation stage 7, and 11 is a vacuum suction groove.
is a vacuum valve, and 12 is a motor.

However, in the apparatus shown in FIG. 11, as shown in FIG. 12, the diameter A of the wafer slice 3 and the diameter B passing through the rotation center P perpendicular to the orientation flat 4 have variations in size. If there is a misalignment between the center of rotation of the rotation stage 7 and the center P of the wafer 3, a shift occurs in the timing at which the sensor 5 is turned on. As a result, the orientation flat 4 cannot be stably stopped at the desired position (or angle).

On the other hand, according to another apparatus shown in FIGS. 13 to 15, when the wafer slice 3 is levitated by the air 14 on the table 13 and the air blowing direction is deviated in the direction of the arrow 15, the wafer slice 3 is pressed toward the idle pulleys 16 and 17 and the drive pulley 18. Next, when the drive pulley 18 is rotated by the motor 19 in the direction of arrow 20 (ie, counterclockwise), the wafer slice 3 is rotated in the direction of arrow 21.
Start rotating in the direction (ie, clockwise). Then, from the point in time when the orientation flat 4 faces the drive pulley 18, the contact between the drive boob IJ-18 and the wafer slice 3 is broken and the rotation stops, resulting in a state as shown in FIG. 15.

However, even in the devices shown in FIGS. 13 to 15,
If there are variations in the dimensions A and B shown in FIG. 12, there is a disadvantage that the rotation stop position of the slice 30 is not constant, and in particular, the slice 3 is in contact with the drive pulley 18 for a long time and is driven to rotate. Harmful dust or scratches are likely to occur on the slice 3.

OBJECT OF THE INVENTION An object of the present invention is to
It is an object of the present invention to provide an apparatus that can accurately position a wafer and minimize the generation of dust and scratches.

20 Structure of the Invention That is, the present invention has at least a movable roller (preferably a fixed roller and a movable roller), a centering means for elastically gripping a wafer (for example, a centering chuck to be described later); a rotating means (for example, a rotation stage described below) that rotates the centering means while rotating; a moving means (for example, a reciprocating mechanism including a return roller described below) that moves the centering means to a position where the movable roller does not contact the wafer during this rotation; Wafer positioning comprising: after the wafer has rotated to a predetermined position, pressing and moving means (for example, a pusher described below) pushes a straight line part (i.e., an orientation flat) around the wafer to move the wafer to a position where the wafer is brought into pressure contact with the movable roller. It is related to the device.

E, Example Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The configuration of the semiconductor wafer positioning device according to this embodiment is explained in the first example.
This will be explained with reference to FIGS. The rotation stage 7, which rotates the wafer while supporting it by vacuum suction, is driven by a motor in the same manner as described in FIG. 11, and has a suction groove 9 connected to a vacuum suction tube. Therefore, on the rotation stage 7, the wafer can be suctioned and fixed or unsuctioned by turning on and off the vacuum pulp. Centering chucks 30 and 3 play an extremely important role in positioning the wafer.
1 are provided in pairs on the left and right, and are movable in parallel along slide shafts 34 and 35, respectively, by reciprocating type air cylinders 32 and 33. On the upper surface of each centering chuck 30 and 31, there is one fixed roller 36, 37 and two movable rollers 38, 39.
40 and 41 are provided. Each movable roller 38-4
1 is a block 4 having a cross-sectional shape as shown in FIG.
The lever 43 is attached to a lever 43 that is rotatably mounted around a support shaft 42 fixed to the
By always biasing in one direction, the rollers 40 and 41 are always biased clockwise (only the rollers 40 and 41). Roller 38.
39, on the contrary, is always biased counterclockwise by a similar mechanism. Note that 45 is an adjustment screw for adjusting the spring force of the compression spring 44, and 46 is a stopper screw for adjusting the position of the movable rollers 40, 41.

In addition, below each centering chuck 30.31,
As shown in FIGS. 3 and 4, the return roller 4
A lever 52 having a number 8 is rotatably attached to a fixed holder 50 by a pin 49 and biased in one direction by a spring 51. Although the drawing shows one centering chuck 30 side, the other centering chuck 31 side is also provided with a mechanism having a return roller similar to the above. FIG. 3 shows the state when the centering chucks 30 and 31 face each other and grip the wafer slice 3 as shown in the imaginary line, and FIG.
Indicates when to separate them. Air cylinder 32.33
Compressed air 55 is passed through conduits 53 and 54 to the air cylinder 3 by operating the air switching valve 56.
2.33 can be set in three states: forward, backward, and intermediate state.

Between both centering chucks 30 and 31, a reflective optical sensor 5 is installed at a predetermined distance from the rotation stage 7.
is arranged, and the image processing camera 6 is arranged above this, which is similar to the apparatus described above. However, air cylinder 5
A button 58 is provided which is actuated at 7.
It is used for the final positioning of the wafer slice as described below.

Next, the operation of the positioning device configured as described above will be explained.

First, the wafer slice 3 is placed on the rotation stage 7, and at this time the orientation flat 4 is generally located in an arbitrary direction. Next, the air switching valve 56 is operated to move the centering chucks 30 and 31 toward each other. This moving distance is determined by the strokes of the air cylinders 32 and 33 (
(See Figure 3). As a result, as shown in FIG. 5, the wafer slice 3 is gripped from both sides between the pair of centering chucks 30-31.
7.38.39.40.41. That is, while the fixed rollers 36 and 37 contact the wafer 3 from both sides, the left and right movable rollers 38 and 39 and 40 and 41 elastically contact the wafer 3, and the shape or size of the wafer 3 is Even if there is a difference as shown in FIG. 7 (when the diameter is large) and FIG. I can do it. Considering that the direction of the orientation flat 4 is arbitrary, the number of rollers 36 to 41 is the minimum required for centering the wafer 3 (i.e.,
It is desirable to have at least six rollers: at least one fixed roller on each side and at least two movable rollers on each side).

In this way, centering of the wafer 3 can always be achieved regardless of its shape and size. and,
Next, when the air switching valve 56 is switched to the neutral state, the space between the centering chucks 30 and 31 is slightly opened (separated) by the action of the return roller 48 urged by the spring 51. The amount of opening is set to a sufficient amount so that the outer periphery of the sea urchin does not come into contact with the movable roller 38, 39, 40, 41 even during rotation to the next sea urchin. At this time, of course, the fixed rollers 36 and 37 do not come into contact with each other.

In this state, the wafer 3 is rotated while being attracted by the rotary stage 7, and the orientation flat 4 is positioned on the sensor 5 side as shown in FIG. At this time, the orientation flat 4 is detected by the sensor 5, and based on this, the motor of the stage 7 is stopped, and the rotation of the wafer 3 is stopped. At this time, the wafer 3 is almost in a state where it faces the wafer 5.

Next, the bushing 58 is moved forward in the direction of the arrow 59,
In the state shown in FIG. 8, the orientation flat 4, which is slightly deviated (that is, the orientation flat 4 is slightly inclined), is pushed as shown in FIG. 9 to correct its position, and the position of the wafer 3 is slightly shifted. As a result, the wafer 3 is brought into pressure contact with the predetermined movable rollers 38, 40 in the directions of arrows 60, 61, so that the wafer 3 is correctly positioned without shifting left or right.

As understood from the above explanation, according to the apparatus of this embodiment, the dimensions (shape, size) of the wafer slice
Even if there is variation in
Even when correcting the position of the wafer slice with the pusher after rotation, it can be pressed against the movable roller and always held in the correct position. Therefore, the wafer slice can always be positioned at the correct position. Furthermore, since the movable rollers (and fixed rollers) do not come into contact with the wafer slice while the wafer slice is rotating, the contact time is minimized and the amount of harmful dust and scratches generated is minimized. I can do it.

Although the present invention has been illustrated above, the embodiments described above can be further modified based on the technical idea of the present invention.

For example, the number and arrangement of the rollers described above can be changed, and the fixed roller of the centering chuck may be omitted in some cases. In addition to the chuck method, other methods can be used for the centering means and rotation means.

As described above, the present invention grips the wafer with a centering means having a movable roller, so that even if there is a variation in the dimensions of the wafer, the variation can be absorbed, and the position of the wafer can be corrected after rotation. Even when moving, it can be held in the correct position by pressing against the movable roller. Therefore, the wafer slice can always be positioned at the correct position. Moreover, since the movable roller does not come into contact with the wafer while the wafer is rotating, the contact time is shortened, and the amount of harmful dust and scratches generated can be reduced.

[Brief explanation of the drawing]

1 to 9 show embodiments of the present invention, in which FIG. 1 is a perspective view schematically showing a semiconductor wafer positioning device, FIG. 2 is an enlarged perspective view of a movable roller portion, and FIG. 4 are partial cross-sectional front views showing how the position of the centering chuck changes. FIGS. 5, 6, and 7 are plan views of main parts showing how the semiconductor wafer is gripped. This figure is a plan view of the main part when the wafer is rotated, and FIG. 9 is a plan view of the main part when the wafer position is corrected. 10 to 15 show conventional examples, in which FIG. 10 is a perspective view of the entire semiconductor wafer positioning device, FIG. 11 is a schematic perspective view of the main parts of the device, and FIG. 12 is a semiconductor wafer positioning device. FIG. 13 is a plan view of the main part of another positioning device, FIG. 14 is a right side view of FIG. 13, and FIG. 15 is a plan view of the main part during positioning. In addition, in the symbols shown in the drawings, 3--...--1--...-Semiconductor wafer 4-...
−・−・−Orientation flat 5−・−・・
−・−(Reflective type) sensor 6・−−−−−−−・−・−・
Image processing camera 7 - - - - - - - One rotation stage 9 - - - - - - - - - Suction groove 30. 31 - - - - - - - - - Centering Chuck 32.33.57--・-----Air cylinder 34.35------------Slide shaft 36.37-----・Fixed rollers 38.39.4o, 41・-Flexible movable roller 42
−・・−・−１−−−・Spindle 44.51−・・−・−−−・・Spring 48・−・・
...--Return roller 56------1.
- Air switching valve 58 - - Pusher. Agent Patent Attorney Hiroshi AisakaFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 11Figure 12

Claims (1)

[Claims] 1. Centering means that includes at least a movable roller and elastically grips the wafer; Rotation means that rotates the wafer while supporting it; and Rotation means that rotates the centering means to a position where the movable roller does not come into contact with the wafer during this rotation. A wafer positioning device comprising a moving means for moving the wafer; and a pressing moving means for moving the wafer to a position where the wafer is brought into pressure contact with the movable roller by pushing a linear portion around the wafer after the wafer has rotated to a predetermined position.