JP2637566B2 - Alignment method and apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment method and apparatus applied to a work table of a semiconductor dicing machine or the like, and more particularly, to a pattern position at a plurality of angles for a reference position of the machine. The present invention relates to an alignment method and an apparatus for performing alignment.

2. Description of the Related Art A semiconductor dicing machine or the like needs to precisely align a cutting line on a wafer surface with a rotary cutting blade. For this purpose, the work table on which the wafer is placed is subjected to the alignment operation for each wafer and for each cutting direction.

The alignment operation starts with reference data registration. Conventionally, for registering reference data, a pattern is registered on channel 1. Next, the work table is rotated from the channel 1 by θ ゜ to be set in the channel 2, and the pattern is stored in the channel 2.

Depending on the accuracy of the alignment, the channel 1 may additionally store a pattern at a lower magnification than the above pattern storage. In the following description, an operation including a low-magnification pattern will be described.

In order to execute the alignment after the reference lens data is registered, first, rough alignment is performed on channel 1 at a low magnification. That is, the work table is moved to perform the rough alignment operation so that the low-magnification pattern stored in the channel 1 matches the current image pattern on the wafer.
Next, fine alignment is performed on channel 1 at a high magnification. That is, the work table is moved so that the high-magnification pattern stored in the channel 1 matches the current image pattern on the wafer, and a fine alignment operation is performed. Next, the work table is rotated by θ チ ャ ン ネ ル from channel 1 and set on channel 2 to perform fine alignment at a high magnification. That is, the work table is moved so that the high magnification pattern stored in the channel 2 matches the pattern on the wafer, and fine alignment in the channel 2 is performed. Thus, the alignment operation ends.

[Problems to be solved by the invention]

However, the conventional alignment method registers a low-magnification and high-magnification reference pattern on channel 1 and registers a high-magnification reference pattern on channel 2, which requires a large amount of time and effort for storing the pattern. There are drawbacks. Further, since the channel 1 and the channel 2 are not related to each other only by being rotated by θ ゜, a means for detecting whether or not there is an error even in a mismatch such as finding a similar pattern at another position. There is no disadvantage.

The present invention has been made in view of such circumstances,
It is an object of the present invention to propose an alignment method and an apparatus which can be easily stored, require a small memory capacity, and have high reliability.

[Means for solving the problem]

The present invention is an alignment method for aligning a cutting line and a cutting blade in the pattern when cutting a work having a pattern such as an IC on the surface, in order to achieve the above object, and rotating the work. In this way, in the alignment method in which alignment is performed on a plurality of channels having different cutting directions, a reference pattern serving as a reference for aligning the work at a rotation position corresponding to the first channel with the first channel is defined. Register the first
Imaging a pattern on the work at a rotation position corresponding to the channel of the work, performing position adjustment on the first channel of the work so that the imaged current image pattern matches the reference pattern, and The reference pattern is rotated from the first channel to a rotation position corresponding to another channel rotated by a predetermined angle θ ゜, and the registered reference pattern is coordinate-transformed so as to rotate by the predetermined angle θ ゜. A reference pattern for the channel is created, a pattern on the work at a rotation position corresponding to the other channel is imaged, and the captured current image pattern matches the created reference pattern for the other channel. In this manner, the position of the work is adjusted in another channel.

Further, according to another aspect of the present invention, the work is moved to the first position.
When rotating from a channel to a rotation position corresponding to another channel rotated by a predetermined angle θ ゜, the imaging unit itself is also rotated, or the current image pattern obtained from the imaging unit is subjected to coordinate conversion to set the current image pattern to a predetermined position. Rotated by an angle θ ゜, and a pattern on the work at a rotation position corresponding to another channel is photographed by the imaging means so that a current image pattern rotated by the predetermined angle θ ゜ coincides with a reference pattern. It is characterized in that the work is aligned in another channel.

[Action]

According to the present invention, it is only necessary to register one reference pattern, which is a reference when positioning a plurality of channels having different cutting directions by rotating the work, regardless of the number of channels. That is, when changing the channel for performing the work alignment from the first channel to another channel having a predetermined angle θ ゜ different cutting direction, the reference pattern is registered so that the registered reference pattern rotates by the predetermined angle θ ゜. The coordinate conversion is performed to create a reference pattern for another channel. As a result, the memory capacity for registering the reference pattern is reduced, and labor for registering the reference pattern can be saved.

Also, instead of rotating the registered reference pattern,
You may make it rotate the current image pattern side obtained from an imaging means. As a mode of rotating the current image pattern side, a case where the imaging unit is rotated by a predetermined angle θ ゜, and a case where the current image pattern obtained from the imaging unit is rotated by a predetermined angle θ
The current image pattern may be coordinate-transformed so as to rotate by ゜.

〔Example〕

Hereinafter, preferred embodiments of an alignment method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, in order to obtain higher accuracy, a pattern image is used at two magnifications of low magnification and high magnification.

FIG. 1 shows the configuration of an alignment apparatus according to the present invention. A wafer 12 is mounted on a work table 10 by suction. The work table 10 is driven in the XY directions by an XY axis drive mechanism 14, and is rotated by a predetermined angle θ ゜ by a rotation drive mechanism 16. The upper surface of the worktable 10 is provided with an air suction mechanism (not shown), whereby the wafer 12 is sucked on the worktable 10 and cut by the rotating grindstone 18 along the cutting line of the wafer 12. A microscope 20 is provided on the work table 10, and this microscope
20 is connected to the imaging unit 22. After the image signal from the imaging unit 22 is A / D converted, the signal is sent to the low-magnification frame memory 26, the high-magnification frame memory 28, and the current image frame memory 30 by the switch 24, respectively. The low-magnification frame memory 26 is connected to the comparator 34 via the switch 32, and the high-magnification frame memory 28 is directly connected to the comparator 34 via the switch 32. Is input to the comparator 34 via the switch 32. The comparator 34 performs a pattern matching process and outputs a pattern matching signal. The output signal from the comparator 34 is input to the controller 38. Further, the controller 38 includes input means such as a keyboard. The controller 38 switches the magnification of the microscope 20 based on input means such as a keyboard,
Further, X-axis direction control, Y-axis direction control, and rotation direction control can be performed based on a signal from the comparator 34.

The alignment operation is performed as follows using the alignment apparatus according to the present invention configured as described above.

FIG. 2 shows a procedure for registering reference data performed prior to the alignment operation. First, in step 40, wafer data is input. That is, wafer data such as the type, diameter, thickness, and pitch of the wafer is input to the controller 38 via a keyboard or the like. Next, in step 42, the first wafer of the master wafer or a similar wafer is
The second wafer is placed on the work table 10 and positioned below the microscope 20. Next, the work table 10 is moved so that the cut line of the wafer in channel 1 is positioned below the microscope 20, and in step 46, the position of the cut line in channel 1 is stored. Next, in step 48, a command to switch to low magnification is issued from the controller 38, the microscope 20 is switched from high magnification to low magnification, and in step 50, the work table 10 is moved to the low magnification pattern position of the channel 1. Move. Further, in step 52, channel 1
Are stored in the memory 26. In this case, the position of the pattern and the pattern shape are stored. Next, in step 54, a signal for switching to high magnification is sent from the controller 38 to the microscope 20, and in step 56, the work table 10 is moved to the high magnification pattern position of the channel 1. The switch 24 is switched to the high magnification frame memory 28, and in step 58, the high magnification pattern for the channel 1 is stored. In this case, the pattern position and the pattern shape are stored. Next, at step 60, a predetermined angle, for example, 90 ° from the channel 1 to the channel 2 is set at 90 °.
Is rotated by the rotation drive mechanism 16. In this case, the data of the rotation center position of the worktable, which is obtained in advance by the initialization operation of the machine, and the channel 1
The same position is obtained by coordinate conversion from the pattern position data of (1).
Further, in step 62, the angle conversion of the high magnification pattern recorded on channel 1 is performed at a predetermined angle θ 所 定. next,
In step 64, the angle-converted high-magnification pattern is compared with the current image pattern, and the channel 2 alignment operation is performed. That is, the address conversion method of the row and column of the high-magnification pattern data in channel 1 is changed and compared with the current image pattern in channel 2. Next, in step 65, the work table 10 is moved to the cut line position.
At 66, the cut line position of channel 2 is recorded. The recording of the reference data is completed as described above.

By the alignment operation in the channel 2, the center position of the work table 10 can be accurately grasped.

Next, an alignment method performed based on the recorded reference data will be described with reference to FIG. First, in step 70, the wafer is positioned below the microscope 20 on the work table 10 by a mechanism (not shown). Next, in step 72, rough alignment based on the low magnification pattern in channel 1 is performed. That is, the low-magnification pattern from the memory 26 is sent to the comparator 34, the current image pattern is sent from the current image memory 30 to the comparator 34, the pattern matching process is performed by the comparator 34, and the result is sent to the controller 38. Then, a drive signal is sent from the controller 38 to the drive mechanism 14, and rough alignment is performed. On the other hand, in step 76, fine alignment based on the high magnification pattern in channel 1 is performed. That is, the switch 32 is switched to the high-magnification frame memory 28 side, the high-magnification pattern is input to the comparator 34, the current image pattern is input from the current image memory 30, and the comparator 34 performs pattern matching processing. The controller 38 drives the worktable 10 based on the matching signal in the high magnification pattern. Next step
At 78, record the cutting position. Next, at step 80, the table is rotated from channel 1 to channel 2 by θ ゜. In step 82, alignment is performed in channel 2 using the high magnification pattern in channel 1. That is, the address conversion method of the row and column of the high-magnification pattern data in channel 1 is changed and compared with the current image pattern in channel 2. That is, the switch 32 is an angle conversion circuit.
The high-magnification pattern is rotated by the angle conversion circuit 36 in accordance with the table rotation angle. The converted high-magnification pattern and the current image pattern are subjected to matching processing by the comparator 34, and the work is performed by the drive signal from the controller 38. table
Drive 40. In step 84, the cutting position and angle at high magnification in channel 2 are stored, and the work table is moved to the cutting position in channel 2.
The alignment operation is completed as described above.

FIGS. 2 and 3 show the alignment data registration and alignment operation from channels 1 to 2, but the present invention is not limited to this. FIG. 4 shows a reference data registration procedure for three channels. FIG. 5 shows an alignment operation in three channels. Conventionally, in the case of three channels, the reference pattern of channel 3 has been registered, but the present invention has the following advantages.

Conventionally, reference data for three channels is required, but storage of reference data for one channel is completed. This can simplify the operation related to the storage of the reference pattern and can reduce the storage area.

When the angle of the channel 3 is 180 ° with respect to the channel 1, the position of the center of rotation of the table can be accurately determined by executing the alignment of the channels 1 and 2. When rotated to channel 3, channel 1
If the position of the reference data and the designated position of the cut line of channel 3 are registered, the position of the cut line of channel 3 can be calculated. Thus, the cut line of the channel 3 can be accurately aligned with the blade without performing the alignment of the channel 3, the operation becomes simpler, and the execution of the alignment is completed in a short time.

FIG. 6 shows a second embodiment according to the present invention.
90 is configured as an interlocking changeover switch, and the switch 90 is sequentially switched so that the low magnification pattern from the memory 26 and the current image pattern from the current image memory 30 are input.
The high magnification pattern is input to the comparator 34 from 28 and the current image pattern is input from the current image memory 30. Further, a high magnification pattern of the channel 1 is inputted from the memory 28, and an image pattern rotated by a predetermined angle by the angle conversion circuit 36 is inputted to the comparator 34. Other operations are the same as in the first embodiment.

In the first and second embodiments, the high-resolution pattern is angle-converted by using the angle conversion circuit 36 and used as a high-magnification pattern in the channel 2. However, the present invention is not limited to this. The image may be rotated, that is, the imaging unit side may be rotated by a predetermined angle. That is, a low-magnification pattern is recorded on channel 1 and a high-magnification pattern is recorded on channel 1 in the same manner as in the first embodiment.
The high-magnification pattern is input to the comparator 34 from 28, and the rotation image pickup unit 22 is rotated by a predetermined angle by the motor 92, and the captured signal is input to the current image memory 32, subjected to matching processing by the comparator 34, and sent to the controller 38. Sent. Other processes are the same.

〔The invention's effect〕

As described above, according to the alignment method and apparatus according to the present invention, a low-magnification pattern is recorded and a high-magnification pattern is recorded in the first channel, and the high-magnification pattern is angle-converted or imaged in other channels. The memory capacity is reduced as compared with the related art since the image pattern is captured by rotating the unit. Also, the operation of registering reference data is simplified. Also, since the memory capacity and the memory procedure can be reduced, for example, when the pattern is compressed and stored, the restoration time is short, and when the memory is dependent on the external storage, the data transfer time is short. In addition, the external storage device can be used for storing the type data because the memory capacity is reduced.

[Brief description of the drawings]

1 is a block diagram showing a schematic structure of an alignment apparatus according to the present invention, FIG. 2 is a flowchart showing a reference registration procedure of an alignment method according to the present invention, and FIG. 3 shows an execution order of an alignment operation according to the present invention. 4 and 5 show an embodiment in the case of three channels, FIG. 4 is a follow chart showing a registration procedure of reference data, FIG. 5 is a flowchart showing an execution order of alignment operation, FIG. FIG. 7 shows another embodiment according to the present invention using the angle conversion of the current image and pattern matching of channel 2, and FIG. 7 shows the present invention which realizes the same operation as FIG. 6 by rotating the imaging unit. It is a block diagram showing such another example. 10 ... Work table, 14 ... XY drive mechanism, 16 ...
Rotation drive mechanism, 20: microscope, 22: imaging unit, 26: frame memory for low magnification, 28 ... frame memory for high magnification, 34
...... Comparator, 36 ... Angle conversion circuit, 38 ... Controller.

Claims (3)

(57) [Claims] 1. An alignment method for aligning a cutting line in a pattern and a cutting blade when cutting a work having a pattern such as an IC on a surface, the method comprising the steps of: In the alignment method for performing alignment using the first channel, a reference pattern serving as a reference for aligning the work located at a rotation position corresponding to the first channel with the first channel is registered, and the first pattern is registered. Imaging a pattern on the work at a rotational position corresponding to a channel, performing alignment of the work on a first channel such that the captured current image pattern matches the reference pattern, While rotating from one channel to a rotation position corresponding to another channel rotated by a predetermined angle θ ゜, the registration is performed. The reference pattern is coordinate-transformed so that the reference pattern thus rotated by the predetermined angle θ ゜ creates a reference pattern for another channel, and a pattern on the work at a rotation position corresponding to the other channel is formed. An alignment method comprising: capturing an image; and performing positioning on another channel of the work such that the captured current image pattern matches the created reference pattern for another channel. 2. An alignment method for aligning a cutting line in a pattern and a cutting blade when cutting a work having a pattern such as an IC on the surface, the method comprising: In the alignment method for performing alignment using the first channel, a reference pattern serving as a reference for aligning the work located at a rotation position corresponding to the first channel with the first channel is registered, and the first pattern is registered. Imaging a pattern on the work at a rotational position corresponding to a channel, performing alignment of the work on a first channel such that the captured current image pattern matches the reference pattern, The image pickup means is rotated from one channel to a rotation position corresponding to another channel rotated by a predetermined angle θ ゜. The current image pattern itself is rotated by the predetermined angle θ ゜, or the current image pattern obtained from the photographing means is coordinate-transformed so as to rotate by the predetermined angle θ ゜, and the current image pattern is at a rotation position corresponding to the other channel. The pattern on the work is photographed by the imaging means, and the position of the work on another channel is adjusted so that the current image pattern rotated by the predetermined angle θ ゜ coincides with the reference pattern. And alignment method. 3. An alignment apparatus for aligning a cutting line in a pattern and a cutting blade when cutting a work having a pattern such as an IC on a surface, wherein the plurality of cutting directions are different by rotating the work. A work placement means having an X-Y direction drive mechanism and a rotation direction drive mechanism; an imaging means for taking an image of a work pattern on the work placement means; Storage means for registering a current image pattern obtained from the imaging means when the work at a rotational position corresponding to a channel is pre-registered as a reference pattern for positioning in a first channel; Means for converting a pattern by a predetermined angle to create a reference pattern for another channel, or The current image pattern obtained through means,
Means for rotating the imaging means itself or rotating by the predetermined angle θ ゜ by performing coordinate conversion on a current image pattern obtained from the imaging means, and comparing the current image pattern from the imaging means with the reference pattern, An alignment apparatus comprising: a pattern matching unit that outputs a pattern matching signal; and a control unit that drives a mounting unit based on an output of the pattern matching unit and outputs a drive signal for aligning a work to a desired position.