JPH0767660B2 - Processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention mounts a workpiece on a mounting table, and controls the movement of the mounting table so that the position where the processing target member is to be machined is set. The present invention relates to a processing machine capable of highly accurately and rapidly positioning a processing tool provided at a predetermined specific position outside the table.

[Conventional technology]

A workpiece such as a semiconductor wafer is fixed to a mounting table that can be moved in the X- and Y-axis directions and the rotation direction, and for example, in a processing machine that cuts into rectangular chips, the cutting is arranged at a predetermined position. It is necessary to drive the mounting table with high accuracy in the X, Y axes or the rotational direction to position the workpiece so that the cutting position of the workpiece is correctly opposed to the blade of the grindstone.

FIG. 2 is a block diagram showing an example of a processing machine.

In FIG. 2, reference numeral 21 denotes a mounting table 21 for a workpiece, a rotary table 22, a Y-axis movable table 23 for displacing the rotary table in the Y-axis direction, and a Y-axis movable table 23.
Is composed of the rotary table 22 and an X-axis movable table 24 for displacing in the X-axis direction. The respective tables 22, 23, 24 are individually driven by drive signals from a drive circuit 25. It is configured as follows.

The member to be processed 26 is placed and held at a predetermined position on the turntable 22 on the placing table 21.

Reference numeral 27 denotes a processing tool drive unit installed at a specific position outside the mounting table 21. For example, in the case of a cutting machine, a rotary cutting wheel 28
The rotation and the up and down directions are driven by respective drive signals guided from the drive circuit 25.

The position of the cutting grindstone 28 corresponds to the above-mentioned specific position, and is movably controlled in the Z-axis direction by a cutting control signal from the drive circuit 25 so that the workpiece 26 can be cut in the X-axis direction.

The specific position is set to a correct position with a known distance from the deviation detecting means 29, the details of which will be described later, and the deviation detecting means 29 is also placed on the rotary table 22. Deviation detection pattern 1 formed at a predetermined position on the processed member 26
Is correctly set to a position where it can be reliably detected.

The deviation detection pattern provided on the member to be processed 26 is formed in a form that can be optically detected, and the deviation detection means 29 has a configuration for coping with this.

That is, the deviation detecting means 29 guides the light flux from the light source 30 to the pattern of the member to be processed 26 via the half mirror 31, and at the same time, the microscope image of the deviation detecting pattern is detected by the line sensor 5.
It is integrally configured so that it can be projected on.

FIG. 1 (A) shows the relationship between the deviation detection pattern 1 formed in advance on the member to be processed and the line sensor 5 of the deviation detecting means.

In FIG. 1 (A), the deviation detection pattern 1 is placed at a predetermined position.
The position 2 of the reference X-axis indicated by the orthogonal coordinate axes of the workpiece to be processed is a fixed specific position outside the mounting table, and coincides with the 0th bit of the line sensor. The description will be made assuming that the alignment line 3 indicated by a broken straight line is aligned.

The deviation detection pattern 1 is formed of, for example, a thin film of aluminum or the like having a high reflection efficiency, and has a wedge shape in which the Y-axis direction changes in the X-axis direction in an axially symmetrical manner about the central axis 4. . With respect to the optical image of the deviation detection pattern 1, the line sensor 5 such as a CCD, which is driven by the deviation detection means, for example, a clock pulse C (see FIG. 2), has a positional relationship as shown in the drawing. In addition, the detection signal from the line sensor 5 when the member to be processed on the mounting table is placed is extracted at the cycle of the clock pulse C that drives the line sensor 5. This is shown in analog form in FIG. 1 (B).
Can be shown in the output waveform diagram. This output waveform corresponds to the linear figure in the Y-axis direction at the position of the line sensor 5 of the deviation detection pattern 1, and includes the pattern width at that position and the position information Yn in the Y-axis direction.

That is, the position information Yn in the Y-axis direction of the central axis 4 corresponding to the distance from the specific position 2 set on the reference X-axis to the central axis 4 of the deviation detection pattern 1 can be easily calculated from the following equation (1). You can ask.

Yn = (n1 + n2) / 2 (1) Further, from the following expression (2), position information in which the Y axis in the X axis direction where the line sensor 5 intersects the deviation detection pattern 1 is the reference specific position 6 Xn can also be easily calculated.

Xn = (n2-n1) / (2tanθ) (2) [Problems to be solved by the invention] FIG. 3 shows the semiconductor wafer 41 as an example of the position where the deviation detection pattern of the workpiece is formed. It is shown.

Dotted lines 42-1 to 42 (n-1) indicate positions in the Y-axis direction to be cut, and 43-1 to 43-m are, for example, IC chips formed on the wafer 41.

In this example, the position of the cutting edge (28 in FIG. 2) of the cutting grindstone fixedly arranged so that the cutting edge coincides with the cutting position is set as the specific position, and the cutting position 42 arranged in the Y-axis direction of the wafer 41 is set at this position. -1 to 42- (n-1) are sequentially aligned.

As shown in FIG. 3, the deviation detection patterns 1-1.1-1-n.
By using the semiconductor wafer 41 with 2n formed, the structure shown in FIG.
The positional information in the X-axis direction and the Y-axis direction can be obtained by using the displacement detection pattern 1-1.1, which is one of the pair of displacement detection patterns 1.1 and 1-1.2. Further, the positional information in the X-axis direction and the Y-axis direction for the deviation detection patterns 1-1 and 2 is obtained, and the positional information is compared to determine the rotational deviation angle in the XY plane of the semiconductor wafer on the mounting table 21. Can be detected.

In the processing machine shown in FIG. 2, the calculation / control circuit 35 supplies a control signal corresponding to the deviation angle to the drive circuit 25 by calculating the rotation deviation angle on the XY plane. Accordingly, the rotation deviation angle is corrected by controlling the rotation angle of the rotary table 22 of the mounting table 21, and the cutting grindstone 28 is also driven in the Z-axis direction with respect to the workpiece by the calculation / control circuit 35. It can be controlled by a command signal.

However, from the deviation detection pattern 1, only positional information in the X-axis direction and the Y-axis direction can be obtained, and the workpiece 26
The position information in the tilt direction (rotational direction) cannot be obtained when the table is mounted on the mounting table 21 while being tilted in the XY plane. Further, in order to increase the detection resolution, the small deviation detection pattern is enlarged to a high magnification by the optical system, and the line sensor 5
Is detected in.

The workpiece 26 is placed on the mounting table 21, and the mounting error is large, so XY
When the device is attached with being inclined on a plane, for example, when detecting the displacement detection pattern 1-1. 1 in FIG. 3 and then detecting the pattern 1-2. 1, the position information in the inclination direction is obtained. It takes time because it is not done.

[Object of the Invention] An object of the present invention is to solve the above problems in the prior art. A deviation that can detect the deviation information in the X and Y axis directions and the tilt direction of the position of the aligned object with respect to a predetermined position. An object of the present invention is to provide a processing machine in which the time required for alignment is shortened by using a detection pattern.

[Means for Solving the Problems]

In the processing machine of the present invention, a member to be processed having a deviation detection pattern is fixed to a mounting table that can be separately moved in the X-axis, Y-axis direction and rotation direction, and the deviation is detected by a deviation detection unit including a line sensor. In a processing machine which detects a deviation from a position detection pattern and corrects it, the deviation detection pattern has a plurality of wedge-shaped patterns arranged in parallel in the Y-axis direction, the wedge-shaped patterns being axisymmetric about an axis parallel to the X-axis. The wedge-shaped patterns have the same inclination angle, and the adjacent wedge-shaped patterns have opposite directions.

〔Example〕

An example of the deviation detection pattern of the processed member 26 in the present invention,
It is shown in FIG. 4 (A), FIG. 5 and FIG. 6, respectively.

It should be noted that these examples are optimal for obtaining the effects of the present invention when applied to the case where the placement error of the workpiece on the placement table 21 is large.

FIG. 4 (A) shows a shape in which two wedge-shaped patterns are combined in opposite directions, with a positional relationship diagram of a projected image on the line sensor 5, as in FIG. 1 (A). .

That is, each of the patterns 44-1 and 44-2 has two axes parallel to the X axis and separated in the Y axis direction as central axes 45-1 and 45-2.
And each wedge shape is axisymmetric, and each wedge shape has the same inclination angle θ of the inclined portion and the opposite direction.

By detecting such a pattern with the line sensor 5 in the same manner as described with reference to FIG. 1 (A), it is possible to obtain a waveform detection output as shown in FIG. 4 (B). As in the previous case, by using the respective count values n1 to n4 obtained by setting the clock pulse of the timing corresponding to the specific position to 0 bit, the following equations (3) and (4) are calculated, thereby The Y-axis position n _Y and the X-axis position n _X corresponding to the pulse number n corresponding to the center of the patterns 44-1 and 44-2 can be calculated.

n _Y = {(n1 + n2) / 2 + (n3 + n4) / 2} / 2 ... (3) n _X = {(n2 + n3) / 2-n} / tan θ ... (4) The table in Figure 4 (A) is
By comparing the distance 1 between n2 and n3 in the state of being placed at the correct position in 21 and the distance 2 between n2 and n3 calculated by the line sensor 5 which is the detection amount, The tilt direction can be determined. Therefore, if the rotary table 22 is controlled based on the information on the distance 1 and the distance 2, the workpiece 26 can be held with a small error in the tilt direction (rotation direction).

The pattern example of FIG. 5 is an example formed by four axisymmetric wedges arranged in the Y-axis direction. In this example, the four wedge-shaped patterns 46-1 to 46-4 have different sizes in the Y-axis direction, and the gaps between the patterns are all formed to be the same, so that the Y-axis and the Y-axis are the same as in FIG. Not only the displacement amount in each direction of the X axis but also the tilt direction can be detected at the same time.

The pattern of FIG. 6 is also designed so that not only the displacement amount in each of the Y-axis and X-axis directions but also the tilt direction can be detected at the same time. In FIG. 6, a wedge-shaped pattern having the same size has a shape in which the widths of the mutual gaps are sequentially changed so as to be alternately opposite in the Y-axis direction, and similar to the example illustrated in FIG. In addition, it is possible to detect each deviation amount with extremely high accuracy.

〔The invention's effect〕

In the processing machine according to the present invention, the deviation detection pattern of the workpiece is a pair of axially symmetric wedges, and the symmetric axes of the pair of wedges are arranged parallel to the X axis and separated in the Y axis direction. The wedge-shaped inclined portions have the same inclination angle and opposite directions.

Therefore, not only the displacement amount in each direction of the Y axis and the X axis,
Since the rotational deviation amount of the coordinate axis can be detected at the same time, the position can be adjusted in a short time and the machining can be efficiently performed.

[Brief description of drawings]

FIG. 1 (A) is an explanatory view of a relationship between a deviation information detecting pattern formed on a member to be processed and a line sensor in a deviation detecting means for detecting the deviation information according to the prior art.
FIG. 1B is an explanatory diagram of the output waveform of the line sensor of FIG. 1A, FIG. 2 is a configuration diagram showing an example of a processing machine according to the prior art, and FIG. FIG. 7 is a front view of a semiconductor wafer showing an example of formation and positions of deviation detection patterns formed on a member. 4 (A) and 4 (B) are explanatory diagrams of the deviation detection pattern and the output waveform of the line sensor in that case according to the present invention.
5 and 6 are views showing the shapes of different deviation detection patterns according to the present invention, respectively. 1, 1-1-1 to 1-n-n, 44-1 to 44-2, 46-1
... 46-4, 47-1 to 47-4 ... deviation detection pattern 2, 6 ... specific position 3 ... position to be positioned at a specific position of the workpiece 4, 45-1, 45-2 …… Center axis of each pattern 5 …… Line sensor, 21 …… Standing table, 22 …… Rotary table, 23 …… Y axis movable table 24 …… X axis movable table 25 …… Drive circuit 26 …… Processing member, 27 …… Processing tool drive unit 28 …… Cutting wheel, 29 …… Displacement detection means 30 …… Light source, 31 …… Half mirror 32 …… Sample hold circuit 33 …… A / D converter, 34… ... Memory 35 ... Arithmetic and control circuit 41 ... Semiconductor wafer 42-1 to 42- (n-1) ... Position to be cut 43-1 to 43-m ... IC chip

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G01B 11/00 H 11/26 H H01L 21/027 21/68 F (72) Inventor Naoki Fujii Saitama Prefectural Tokorozawa, Shimotomi 840 Takeno, Citizen Watch Co., Ltd. Technical Research Institute (72) Inventor, Toshikazu Hatase, Tokorozawa, Saitama Prefectural Shimotomi 840, Citizen Watch Co., Ltd. 5-33-1, Shiba, Minato-ku, NEC Corporation (72) Inventor Toshiro Wada 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sumitomo Special Metals Co., Ltd. Yamazaki Works (72) Inventor Nakaoka Junichi 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sumitomo Special Metals Co., Ltd. Yamazaki Manufacturing Co., Ltd. (56) Reference JP-A-60-225002 (JP, A) JP-A-51-64682 ( P, A) JP Akira 60-260127 (JP, A)

Claims (1)

[Claims] 1. A member to be processed having a deviation detection pattern,
It is fixed to a mounting table which can be moved in the X-axis, Y-axis direction and rotation direction separately, and by the deviation detecting means including a line sensor,
In a processing machine that detects a deviation from a deviation detection pattern and corrects the deviation, the deviation detection pattern includes a plurality of wedge-shaped patterns in the Y-axis direction that are axisymmetric about an axis parallel to the X-axis. A processing machine, which is arranged in parallel, wherein the inclination angles of the inclined portions of the respective wedge-shaped patterns are equal, and the directions of adjacent wedge-shaped patterns are opposite.