JPH10321707A - Wafer pre-alignment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer pre-alignment device which can correctly pre-align a wafer regardless of the material of the wafer. SOLUTION: A roller 20 is pressed on the outer periphery of a wafer W to rotate the wafer by one revolution. Since the roller 20 is displaced most at the center of the orientation flat of the wafer W, the position of the orientation flat is found from the displacement of the roller 20. The wafer W is pre- aligned by rotating the wafer W based on the found position, such that the orientation flat is positioned in a predetermined direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer pre-alignment apparatus, and more particularly to a wafer pre-alignment apparatus for positioning a wafer at a predetermined position before inspecting the wafer with a wafer inspection apparatus such as a prober.

[0002]

2. Description of the Related Art Before a wafer is placed on a chuck by a prober or the like, an operation of adjusting its angular direction to a predetermined direction is performed in advance. This operation is called pre-alignment. Conventional pre-alignment has been performed by the following method. First, a wafer is placed on a wafer table, and light is emitted from a light projecting unit toward an outer peripheral portion of the placed wafer. Then, the wafer is rotated once in this state. The light emitted from the light projecting unit is received by the light receiving unit. However, since the orientation flat (or notch) is formed on the outer peripheral portion of the wafer, when the wafer is rotated once, the orientation flat is The amount of light received by the light receiving unit changes in a portion. The position of the orientation flat formed on the wafer is determined from the changing amount of received light, and the wafer is rotated so that the orientation flat is positioned in a predetermined direction, thereby adjusting the angular direction of the wafer to a predetermined direction.

[0003]

However, in the above method, when the material of the wafer is a transparent material such as glass and a pattern is formed on the surface, the change in the light quantity of the orientation flat (or notch) is used. However, since there is a larger change in the amount of light depending on the presence or absence of a pattern, it is difficult to perform accurate pre-alignment.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wafer pre-alignment apparatus capable of accurately pre-aligning a wafer regardless of the material of the wafer.

[0005]

In order to achieve the above object, the present invention detects the position of an orientation flat or notch formed on the outer periphery of a wafer, and positions the orientation flat or notch in a predetermined direction. In a wafer pre-alignment apparatus that positions a wafer at a predetermined position, a wafer table that supports the wafer, a motor that rotates the wafer table, and a reciprocally movable unit that is provided with respect to the wafer supported by the wafer table are provided. A moving member, an urging member for urging the moving member in the direction of the wafer, and pressing the moving member against the outer periphery of the wafer; and a displacement of the moving member pressing and contacting the outer periphery of the wafer. Detection means for detecting the rotation of the motor, the detection means when one rotation of the motor is formed on the wafer from the detection result Indexing the position of the orientation flat or notch, and wherein the control means the orientation flat or notch controls the rotation of the motor so as to be positioned in a predetermined direction, in that it consists of.

According to the present invention, the position of the orientation flat or notch formed on the wafer is determined from the displacement of the moving member pressed against the outer periphery of the wafer, and the wafer is pre-aligned. That is, when the wafer is rotated once, the position of the moving member pressed against the outer peripheral portion of the wafer is displaced at the orientation flat portion or the notch portion of the wafer. The position of the orientation flat or notch formed on the wafer is determined from the displacement amount of the moving member when the wafer is rotated once, and the wafer is rotated so that the orientation flat or notch is located in a predetermined direction. Perform pre-alignment.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a wafer pre-alignment apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing a configuration of an embodiment of a wafer pre-alignment apparatus according to the present invention, and FIG. 2 is a side view thereof.

As shown in FIG. 1, the wafer pre-alignment apparatus 10 includes a wafer holding unit 12 for holding a wafer W, and a roller for pressing a roller 20 against the outer periphery of the wafer W held by the wafer holding unit 12. The driving unit 14 and the roller 2 pressed against the outer periphery of the wafer W
It comprises a displacement detecting section 16 for detecting a displacement of 0 and a control section 18 for controlling the apparatus.

First, the configuration of the wafer holding unit 12 will be described. As shown in FIGS. 1 and 2, a cylindrical housing 24 is provided on the base plate 22. A motor (not shown) is built in the housing 24, and a wafer table 26 is connected to a spindle of the motor. The wafer W is placed on the wafer table 26 and vacuum-sucked, so that the wafer table 26
Held on. Then, the wafer W held on the wafer table 26 is rotated by driving a motor built in the housing 24.

Next, the configuration of the roller driving section 14 will be described. At a substantially central position on the base plate 22, a first guide rail 28 is laid along a vertical direction in the figure. A slide base 32 is slidably supported on the first guide rail 28 via a slider 30. A cylinder 34 is arranged near the left side of the first guide rail 28 along the direction in which the first guide rail 28 is laid. The slide base 32 is connected to the rod of the cylinder 34 via a connecting member 36, and slides on the first guide rail 28 by expanding and contracting the rod of the cylinder 34. The slide base 32 moves in a direction approaching the wafer table 26 (upward in FIG. 1) by extending the rod of the cylinder 34, and contracts the rod of the cylinder 34 to cause the wafer to move. It moves in a direction away from the table 26 (downward in FIG. 1).

The first base is provided on the slide base 32.
A second guide rail 38 is laid in the same direction as the laying direction of the guide rail 28. This second guide rail 38
A slide plate 42 is slidably supported on the upper side via a slider 40. The slide base 32 and the slide plate 42 are connected to each other by a spring 44. That is, the spring 44 has one end connected to the pin 32A planted on the slide base 32 and the other end connected to the pin 42A planted on the slide plate 42. As a result, the slide plate 42 is always urged by the action of the spring 44 in a direction approaching the wafer table 26 (upward in FIG. 1).

The roller 20 for pressing and contacting the outer periphery of the wafer W is rotatably supported by a tip end of a column 46 erected on the slide plate 42. Here, a case in which the roller 20 is pressed against the outer periphery of the wafer W held on the wafer table 26 will be described. First, with the rod of the cylinder 34 contracted, the wafer W is placed on the wafer table 26.
Is placed. At this time, the wafer W is placed so that the center of the wafer W coincides with the rotation center of the wafer table 26. Then, after placing the wafer W, the wafer W is vacuum-sucked and held on the wafer table 26.

Next, the rod of the contracted cylinder 34 is extended by a predetermined amount. Since the slide base 32 is connected to the rod of the cylinder 34, when the rod is extended, the slide base 32
Moves on the first guide rail 28 in a direction approaching the wafer table 26 (upward in FIG. 1). Here, the slide plate 42 provided with the roller 20 is provided.
Is provided on the slide base 32. Therefore, when the slide base 32 moves, the roller 20 also moves toward the wafer W held on the wafer table 26. As a result, the roller 20 moves the wafer W on the wafer table 26.
Abuts the outer periphery of

The pressing force by which the roller 20 presses the outer periphery of the wafer W is generated as follows. Since the slide base 32 is connected to the rod of the cylinder 34, the slide base 32 moves by the same amount of extension of the rod. Therefore, the slide base 32 moves to a predetermined position (hereinafter, referred to as a pressing position) when the rod of the cylinder 34 extends a predetermined amount.

On the other hand, the roller 20 abuts on the outer periphery of the wafer W before the slide base 32 reaches the pressing position. Therefore, after the roller 20 comes into contact with the outer periphery of the wafer, only the slide base 32 moves. Here, since the slide base 32 and the slide plate 42 are connected by a spring 44, the slide base 3
When only 2 moves, the springs 4 connecting them together
4 expands. As a result, the roller 20 is pressed against the outer periphery of the wafer W by the urging force of the spring 44.

As described above, the roller 20 pressed against the outer periphery of the wafer W always contacts the outer peripheral surface of the wafer W and can follow the outer peripheral surface of the wafer W.
Next, the configuration of the displacement detection unit 16 will be described. On the base plate 22, a post 48 is erected vertically. On the post 48, a light emitting unit 50 and a light receiving unit 52 are horizontally supported at predetermined intervals.

The light projecting unit 50 is provided with a light projecting unit 54, and the light receiving unit 52 is provided with a light receiving unit 56 facing the light projecting unit 54. The light emitting unit 54 emits light toward the light receiving unit 56, and the light receiving unit 56 detects the amount of light emitted from the light emitting unit 54. Then, the light receiving section 56
The detected value of the amount of received light detected at is output to the control unit 18.

A light-blocking member 58 for blocking light emitted from the light projecting section 54 is disposed between the light projecting section 54 and the light receiving section 56. The light blocking member 58 is fixed to the slide plate 42 and moves in conjunction with the movement of the slide plate 42, that is, the movement of the roller 20, and blocks the amount of light emitted from the light projecting unit 54. I do. As a result, the amount of light received by the light receiving section 56 corresponds to the displacement of the roller 20 on a one-to-one basis.

As described above, the amount of light received by the light receiving unit 56 is output to the control unit 18. Control unit 18
Calculates the displacement of the roller 20 based on the detection result by a built-in arithmetic unit. Then, the controller 18 calculates the position of the orientation flat OF or the notch NO formed on the wafer W from the displacement of the roller 20 when the wafer W is rotated once, and
The rotation of the wafer table 26 is controlled so that F or the notch NO is located in a predetermined direction.

The operation of the embodiment of the wafer pre-alignment apparatus according to the present invention configured as described above is as follows. First, the wafer W is placed on the wafer table 26 with the rod of the cylinder 34 contracted. At this time, the center of the wafer W and the wafer table 2
The wafer W is mounted so that the rotation center of the wafer 6 coincides with the center of rotation. Then, after placing the wafer W, the wafer W is vacuum-sucked and held on the wafer table 26.

Next, the contracted rod of the cylinder 34 is extended by a predetermined amount. As a result, the slide base 3
2 is located at a predetermined pressing position, and
Is the wafer W held on the wafer table 26
Is pressed against the outer periphery of the. When the roller 20 is pressed against the outer periphery of the wafer W, the wafer table 2
6 is driven, and the wafer W makes one rotation (rotates 360 °). At the same time, the displacement detector 16 detects the displacement of the roller 20.

Here, the roller 20 abutting on the outer periphery of the wafer W always abuts on the outer periphery of the wafer W and moves following the outer peripheral surface of the wafer W. Therefore, while not in contact with the circular portion of the wafer W, there is no displacement,
The wafer W is displaced by contact with the orientation flat OF of the wafer W. Since this displacement is maximum at the center of the orientation flat OF, the position of the orientation flat OF can be determined by detecting at which position the displacement is maximum when the wafer W is rotated once. .

If the position of the orientation flat OF is detected, the rotation of the wafer W
Is calculated in a predetermined direction, the wafer table W is rotated by a predetermined amount and the orientation flat OF is positioned in a predetermined direction based on the calculation result. For example, the direction in which the orientation flat OF should be aligned is 9
It is assumed that the direction is set to 0 °. And roller 2
It is assumed that the maximum value of the displacement of 0 is detected at a position 20 ° from the start of detection. In this case, if the wafer W is rotated by 70 °, the orientation flat OF is located at a predetermined position.

As described above, according to the wafer pre-alignment apparatus of the present embodiment, the position of the orientation flat OF of the wafer W is determined from the displacement of the roller that presses and abuts on the outer peripheral portion of the wafer W. Pre-alignment can be performed accurately even for the wafer W of the above. In the above-described embodiment, the case where the wafer W with the orientation flat is pre-aligned has been described. However, in the case of the notch wafer, a small-diameter roller (needle-shaped) is used instead of the roller 20 shown in FIG. To detect. Thereby, the displacement can be detected along the shape of the notch.

In this embodiment, the displacement of the roller 20 is detected by the optical detection means. However, the present invention is not limited to this, and another detection means may be used.

[0026]

As described above, according to the present invention,
Prealignment can be performed accurately for wafers of any material.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of a wafer pre-alignment apparatus according to the present invention.

FIG. 2 is a side view of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer pre-alignment apparatus 12 ... Wafer holding part 14 ... Roller drive part 16 ... Displacement detection part 18 ... Control part 20 ... Roller 26 ... Wafer table 34 ... Cylinder 42 ... Slide plate 44 ... Spring 54 ... Light emitting part 56 ... Light receiving Part 58: light shielding member W: wafer OF: orientation flat

Claims (3)

[Claims] 1. A wafer pre-alignment apparatus for detecting the position of an orientation flat or notch formed on the outer periphery of a wafer, positioning the orientation flat or notch in a predetermined direction, and positioning the wafer at a predetermined position. A wafer table for supporting a wafer; a motor for rotating the wafer table; a moving member provided to be able to move forward and backward with respect to the wafer supported on the wafer table; and urging the moving member toward the wafer. And an urging member for pressing the moving member against the outer periphery of the wafer; a detecting unit for detecting displacement of the moving member pressed against the outer periphery of the wafer; and when the motor is rotated once. The position of the orientation flat or notch formed on the wafer is determined from the detection result of the detection means of Control means for controlling the rotation of the motor so that the hula or the notch is located in a predetermined direction. 2. The light emitting unit, a light receiving unit provided opposite to the light emitting unit, and a light receiving unit connected to the moving member, and between the light emitting unit and the light receiving unit. The light-shielding member is arranged, and moves in conjunction with the displacement of the moving member, so as to block part or all of the light emitted from the light-emitting unit, and 2. The wafer pre-alignment apparatus according to claim 1, further comprising: a calculating unit that calculates a displacement of the moving member. 3. The wafer pre-alignment apparatus according to claim 1, wherein the wafer to be pre-aligned is a transparent wafer.