JP5057489B2 - Alignment apparatus and alignment method - Google Patents

Description

  The present invention relates to an alignment apparatus and an alignment method, and more particularly, to an alignment apparatus and an alignment method capable of accurately recognizing and positioning a wafer having a damaged outer peripheral portion.

Conventionally, a wafer is placed between a laser projector and a light receiver, the wafer is rotated in a plane, the transmitted laser light is detected by the light receiver, and the center of the wafer is centered on the amount of received light and how it changes. 2. Description of the Related Art An alignment apparatus is known in which a wafer is positioned by obtaining or recognizing a V-notch (see, for example, Patent Document 1).
Also, as is done with a prober or dicing machine, the street before dicing is detected by image processing, the angle of the street is determined, the angle is corrected, and the chip to be probed first on the outermost part of the wafer There is also known an alignment apparatus that obtains a position or obtains a street line to be diced first.
These apparatuses are effective when a wafer before dicing is targeted.

JP-A-10-242250

However, recently, the outer peripheral portion of the wafer is often damaged as the so-called tip dicing method in which the wafer is diced after the wafer is diced and the wafer is thinned. For example, a chip or the like accompanying grinding at other parts on the outer periphery of the wafer may occur in a shape that approximates the orientation mark of the wafer.
Therefore, when positioning is performed on a wafer having a damaged outer peripheral portion, erroneous recognition is likely to occur in the conventional alignment apparatus, which is a disadvantage in that the production efficiency is lowered.

[Object of invention]
The present invention has been devised by paying attention to such inconveniences, and the object thereof is to detect a dicing line and to limit the detection area of the azimuth mark in association with the dicing line so that there are few misrecognitions. An alignment apparatus and an alignment method are provided.

In order to achieve the above object, the present invention is provided for holding a wafer which is provided so as to hold a wafer and be rotatable in a plane, and to be movable along predetermined X and Y axes orthogonal to each other in the same plane. In an alignment apparatus comprising a table, detection means having a function of detecting the center position of the wafer, and drive means for the table,
The wafer, in the plane of its being pre-diced, the dicing lines are formed, the orientation marks of substantially V-shaped is provided in any one of the wafer periphery of the four places in the extending direction of the dicing lines And
The detecting means detects the edge of the wafer by rotating the wafer and obtains the center position of the wafer, and captures and recognizes a two-dimensional image of the dicing line and detects its extending direction. A function and a function of detecting an orientation mark provided on the outer periphery of any one of four locations in the extending direction of the dicing line,
The driving means adopts a configuration in which the table is driven so that the wafer is positioned at a predetermined position by correcting the wafer center position shift and the azimuth mark position angle shift based on the detection result.

The present invention also provides a wafer holding table that is provided so as to be able to hold a wafer and rotate in a plane, and to be movable along the X and Y axes orthogonal to each other in the same plane, and the center of the wafer. Using an alignment apparatus having a detecting means having a function of detecting a position and a driving means for the table,
The wafer, in the plane of its being pre-diced, the dicing lines are formed, the orientation marks of substantially V-shaped is provided in any one of the wafer periphery of the four places in the extending direction of the dicing lines And
The wafer is rotated and the edge of the wafer is detected by the detection means to obtain the center position of the wafer, and the detection means captures and recognizes a two-dimensional image of a dicing line formed in the wafer surface. And detecting the extending direction, and detecting an orientation mark provided on the outer periphery of the wafer in any one of four locations in the extending direction of the dicing line,
A method is adopted in which the table is driven so that the wafer is positioned at a predetermined position by correcting the wafer center position shift and the orientation mark position angle shift based on the detection result.

  According to the present invention, by recognizing one direction of the orthogonal dicing lines, the possibility of existence of orientation marks such as V notches in the vicinity of four wafer edges in the extending direction of the dicing lines is estimated. Since the orientation mark can be detected by limited inspection with the inspection means, even if defects such as a chip that may occur on the wafer edge exist in a confusing state, the orientation mark can be efficiently distinguished and distinguished from this. Can be recognized. Therefore, it is possible to provide an alignment apparatus and an alignment method that have an unprecedented excellent effect that the accuracy of positioning the wafer on the table at a predetermined position can be improved.

The schematic block diagram of the alignment apparatus which concerns on this embodiment. The schematic plan view for demonstrating the positioning method in the said embodiment. The schematic plan view for demonstrating the other positioning method.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an overall configuration diagram of an alignment apparatus according to the present embodiment. In this figure, an alignment device 10 includes a table 11 for holding a wafer W transferred via a transfer device such as a robot arm (not shown), a driving means 12 for driving the table 11, and the wafer W. A detecting means 13 for recognizing the center position and the extending direction of the dicing line and detecting the azimuth mark position as position information, and driving the driving means 12 based on the position information of the wear W detected by the detecting means 13. And a control device 14 for predetermined positioning of the wafer W. Here, in this embodiment, as shown in FIG. 2, a dicing line L having a grid shape is formed in advance, and a V notch (orientation mark) N is formed in the outer peripheral portion (edge portion). The wafer W is a positioning target.

  The table 11 has a large number of vacuum holes on its upper surface, and can hold the wafer W in a fixed state by sucking the lower surface side of the wafer W placed on the upper surface. Adsorption is released when the wafer W after being positioned is transferred to the next process.

  The drive means 12 includes a rotary stage 16 that rotates the table 11 in a plane, and an X-axis stage 17 that is positioned below the rotary stage 16 and moves the table 11 in the X-axis direction (left-right direction in FIG. 1). And a Y-axis stage 18 that is positioned below the X-axis stage 17 and moves the table 11 in the Y-axis direction (the direction perpendicular to the paper surface in FIG. 1). A known unit using various motors, cylinders, ball screws, linear guides and the like is employed as a mechanism for driving each of the stages 16 to 18.

The detection means 13 includes a first camera 20 disposed relative to the wafer W above the table 11, an illumination 20P for irradiating the target area, a lens 20L for imaging the target area on the camera, a first A second camera 21 provided adjacent to one camera 20, an illumination 21P for illuminating the target area, a lens 21L for imaging the target area on the camera, and the first and second cameras 20 and 21 mutually. It is comprised by the external appearance sensor 22 which acts and comprises a detection means. In the present embodiment, the first camera 20 is set to detect the dicing line L, while the second camera 21 is set to detect the edge region of the wafer W including the notch N. Here, the resolution of the first camera 20, the lens 20L attached thereto, and the illumination 20P is set to be higher than the resolution of the second camera 21, the lens 21L attached thereto, and the illumination 21P. This is due to the following reason. That is, the line width of the dicing line L is affected by the expansion and contraction of the dicing tape that is the wafer support material during dicing even if the dicing blade is 30 μm wide, for example. The minimum value is about 10 μm. On the other hand, since the V notch N usually has a width of several millimeters, it is sufficient to use a relatively low resolution of the second camera 21 for detecting this.
On the other hand, it is of course possible to configure with only the first camera 20 that detects the dicing line L, the lens 20L, and the illumination 20P. In short, it is only necessary that one camera can detect the direction of the dicing line and the outer periphery of the wafer including the orientation flat and the V notch.
Returning to the description of the case of the two-camera configuration, it goes without saying that the resolution depends on the lens magnification and the pixel arrangement of the camera image pickup device represented by the CCD or the like. For example, the magnification of the lenses 20L and 21L may be 10: 1. In this case, the imaging area is approximately an area ratio of 100: 1. Of course, a lens having a resolution switching function may be used, and switching may be performed according to a target portion for detecting them.
In the above description, the image pickup device of the camera has been described with a two-dimensional area sensor in mind, but even when a line sensor in which light receiving elements are arranged in a straight line is used, a configuration that captures a two-dimensional image is configured exactly as described above. be able to.

  The control device 14 has a function of performing predetermined processing based on the position information of the wafer W and the position information of the table 11 by the detection means 13. That is, the control device 14 specifies the extending direction of the dicing line L and the center position of the wafer W from the position information obtained by the inspection unit 13, and the rotation center C of the table 11 (see FIG. 1) at a predetermined position set in advance. ) As the origin, the amount of deviation between the origin of the coordinate system having the X-axis and Y-axis extending in two directions orthogonal to this and the wafer center position, and the deviation in the extending direction of the dicing line L with respect to the X-axis or Y-axis A calculation function for obtaining the angle, a function of rotating the table 11 based on the calculation result, and a function of energizing the driving means 12 so that the dicing line L coincides with either the X axis or the Y axis, The table 11 is rotated by a predetermined angle to detect the V notch N, and the table is provided via the driving means 12 so that the rotation center of the wafer W and the V notch are positioned at the predetermined position. It is configured to include the function of controlling the 1.

  Next, a specific mode of positioning in the present embodiment will be described with reference to FIG.

  As an initial setting, an initial setting is performed in which the rotation center C of the table 11 coincides with the origin O of the X and Y coordinates that specify the predetermined position, and the wafer is diced on the table 11 via a transfer device (not shown). Transfer W. This transfer is performed in such a direction that the dicing line L is exposed to the upper surface side. The wafer W is transferred via a transfer device, and the position of the V notch N tends to vary widely around the origin O, but the position of the center C1 of the wafer W is relative to the origin O. It can be said that there is practically no significant deviation.

  Next, the table 11 is rotated at intervals of a predetermined angle (for example, 120 degrees). Then, the wafer edge is detected by the second camera 21, and the center position C1 of the wafer W is obtained by the processing device 14 based on the data given from the appearance sensor 22, so that the X axis, Y of the wafer center C1 with respect to the origin O A deviation amount with respect to each axis is specified. Further, after the first camera 20 recognizes the extending direction of the dicing line L along one direction, the control device 14 obtains an angular deviation amount of the dicing line L with respect to the X axis or the Y axis, and in response to this, The table 11 is rotated via the driving device 12 so that the dicing line L is parallel to the X axis or the Y axis.

  In the state where the dicing line L is parallel to the X axis or the Y axis in this way, in the case of FIG. 2, it is presumed that the V notch N which is the orientation mark is in the regions S1 to S4. Therefore, erroneous recognition can be avoided by detecting the V notch N with the second camera 21 in these areas S1 to S4.

  After the detection of the V notch N, the table 11 is moved in the X and Y axis directions so that the center position C1 of the wafer W coincides with the origin O position. What is necessary is just to move so that it may be located in the upper side on a middle Y-axis line, and, thereby, the wafer W can be positioned in a predetermined position. Thereafter, the adsorption of the wafer W by the table 11 is released, and the wafer W can be transferred to the next process stage via a transfer device (not shown).

  At the time of positioning, the rotation center C of the table 11 has moved to a position deviated from a preset origin O. However, after the transfer of the wafer W after positioning is completed, the rotation center C is moved. Is returned to the initial position coinciding with the origin O.

  Therefore, according to such an embodiment, since the region for detecting the V notch N is limited, it is possible to effectively avoid erroneous recognition due to defects or the like that may exist in the edge region of the wafer W. Thus, the wafer W can be positioned with high accuracy.

The best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this.
That is, the invention has been illustrated and described with particular reference to particular embodiments, but it should be understood that the above-described embodiments are not deviated from the technical idea and scope of the invention. On the other hand, various modifications can be added.
Accordingly, the configurations and methods disclosed above are described in an exemplary manner for facilitating the understanding of the present invention, and are not intended to limit the present invention. Variations are included in the present invention.

  For example, in the above-described embodiment, the case where the coordinate system having the X and Y axes orthogonal to the rotation center C of the table 11 is used is shown. A coordinate system having X and Y axes with C1 as the origin may be used, and the V notch N may be detected with the dicing line L parallel to the X axis and Y axis. According to such a method, as shown in FIG. 3, it becomes possible to detect the V notch N by narrowing down the regions S1 to S4 where the V notch N is to be inspected. In FIG. 3, the X and Y axes indicated by the alternate long and short dash line indicate the coordinates with the rotation center C of the table as the origin, and the X and Y axes indicated by the dotted line indicate the center C1 of the wafer W as the origin. The coordinates are shown. Here, in order to avoid complication of the drawings, the X and Y axis positions in each coordinate are shifted by about 45 degrees, but in practice, it is preferable to set the positions at substantially the same position.

DESCRIPTION OF SYMBOLS 10 Alignment apparatus 11 Table 12 Drive means 14 Control apparatus 20 1st camera (detection means)
21 Second camera (detection means)
22 Appearance sensor (detection means)
W Wafer L Dicing Line N V Notch (Direction Mark)
C Center of rotation (origin)

Claims (2)

A wafer holding table that is provided so as to be able to hold and rotate in a plane and to move along predetermined X and Y axes orthogonal to each other in the same plane and a center position of the wafer are detected. In an alignment apparatus comprising a detecting means having a function and a driving means for the table,
The wafer, in the plane of its being pre-diced, the dicing lines are formed, the orientation marks of substantially V-shaped is provided in any one of the wafer periphery of the four places in the extending direction of the dicing lines And
The detecting means detects the edge of the wafer by rotating the wafer and obtains the center position of the wafer, and captures and recognizes a two-dimensional image of the dicing line and detects its extending direction. A function and a function of detecting an orientation mark provided on the outer periphery of any one of four locations in the extending direction of the dicing line,
The driving device drives the table so that the wafer is positioned at a predetermined position by correcting the wafer center position shift and the azimuth mark position angle shift based on the detection result. A wafer holding table which is provided so as to be able to hold a wafer and rotate in a plane, and to be movable along X and Y axes orthogonal to each other in the same plane, and a function of detecting the center position of the wafer. Using an alignment apparatus comprising detection means having the table drive means,
The wafer, in the plane of its being pre-diced, the dicing lines are formed, the orientation marks of substantially V-shaped is provided in any one of the wafer periphery of the four places in the extending direction of the dicing lines And
The wafer is rotated and the edge of the wafer is detected by the detection means to obtain the center position of the wafer, and the detection means captures and recognizes a two-dimensional image of a dicing line formed in the wafer surface. And detecting the extending direction, and detecting an orientation mark provided on the outer periphery of the wafer in any one of four locations in the extending direction of the dicing line,
An alignment method comprising: driving a table so that a wafer is positioned at a predetermined position by correcting a wafer center position shift and an orientation mark position angle shift based on the detection result.

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