JPH03287347A - Alignment method and its device - Google Patents

Abstract

PURPOSE:To carry out the alignment without registering the reference data even though the sort of substance is changed by photographing and storing marks provided on a wafer, and positioning depending on the positions and the forms of the marks. CONSTITUTION:A microscope 20 is moved to the position of a mark 52 of a wafer 56, the picture image data is taken in to a frame memory 30 for present picture image, the wafer 56 is moved while comparing the picture image data with a reference data in a comparator 34, the position where the reference data is coincident to the new data is sought, and the first position of the wafer 56 at that time is stored. Then, the microscope 20 is moved to the marking position of the other mark 5, and the second position of the wafer 56 where the registered data is coincident to the new data is stored. And from the first position and the second position, the wafer 56 is rotated making the parallel of the movement axis X and the movement axis Y of the alignment device coincident so as to unify the parallels. And after that, the wafer 56 is moved depending on the parameter prescribed from the pre-registered coordinates.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an alignment method and apparatus applied to work tables of semiconductor dicing machines, probing machines, etc. The present invention relates to an alignment method and apparatus for aligning with a reference position.

[Conventional technology]

Semiconductor dicing machines, probing machines, and the like require precise alignment between cutting lines on the wafer surface and rotating cutting blades. For this reason, the work table on which the wafer is placed is subjected to alignment operations for each wafer and also for each cutting direction.

The alignment operation begins with the registration of reference data. Conventionally, reference data is registered by registering a pattern on channel 1. Next, rotate the work table θ° from channel 1 and set it on channel 2.
Store the pattern on channel 2.

To execute alignment after registering reference data,
First, alignment is performed on channel 1.

That is, an alignment operation is performed by moving the work table so that the pattern stored in channel 1 and the current image pattern on the wafer match. Next, move the work table from channel 1 to θ.

Rotate it, set it in channel 2, and perform alignment. That is, the work table is moved so that the pattern stored in channel 2 matches the pattern on the wafer, and alignment in channel 2 is performed. This completes the alignment operation.

Note that in the case of a blobbing machine or the like, alignment may be performed only on channel 1.

[Problem to be solved by the invention]

However, since the pattern shape of the wafer differs depending on the type of Ueno\, there is a problem in that each time the type of Ueno\ changes, a new pattern shape must be registered as reference data.

The present invention has been made in view of the above circumstances, and provides an alignment method and apparatus that can align wafers without newly registering the notch shape as reference data even if the type of wafer changes. The purpose is to provide.

[Means to solve problems]

In order to achieve the above-mentioned object, the present invention provides an alignment method in which a part of a Ueno having a pattern such as an IC on its surface is imaged and stored, and the Ueno is positioned at a desired position based on the imaged and stored pattern. , a mark of a prescribed shape is provided at a prescribed position on each wafer, the mark is imaged and stored, and the wafers are aligned based on the position and shape of the same mark as the previously stored mark.

[Effect]

According to the present invention, a mark with a specified shape is provided at a specified position on the wafer, so that once the position where the mark is provided and the shape of the mark are registered, even if the type of Ueno\ changes, a new Ueno\ Wafer alignment can be performed without registering patterns.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the alignment method and apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of an alignment apparatus according to the present invention, in which a wafer 12 is placed on a work table 10 by suction. The work table 10 has an X-Y axis drive mechanism 1
4 in the X-Y direction, and a rotational drive mechanism 16
The predetermined angle θ is determined by θ.

It is designed to be rotated. An air suction mechanism (not shown) is provided on the upper surface of the work table 10, whereby the wafer 12 is suctioned onto the work table 10, and the wafer 12 is cut along the cutting line by a rotary grindstone 18. A microscope 20 is provided on the work table 10, and this microscope 20 is connected to an imaging section 22. After the image signal from the imaging unit 22 is A/D converted, it is sent to the registration frame memory 28 and the current image frame memory 3 by the switch 24.
0 respectively. Further, the registration frame memory 28 is connected to a comparator 34. The comparator 34 performs pattern matching processing and outputs a pattern matching signal. The output signal from the comparator 34 is manually input to a controller 38. The controller 38 also includes input means such as a keyboard.

The controller 38 can perform X-axis direction control, Y-axis direction control, rotation direction control, etc. based on the signal from the comparator 34 based on input means such as a keyboard.

On the other hand, marks 52, 52, . . . are provided on the wafer 12 at a central position and at a constant distance from the wafer periphery, as shown in FIG. 2(A).

As shown in FIG. 2(B), the mark 52 has a rectangular outer shape and a cross inside thereof, which is a specific shape with sufficient contrast. This mark 52
is not limited to the cross, but other patterns may be used as long as the contrast is sufficient.

Furthermore, the size of the pattern is set based on the magnification of the optical system provided in the alignment device.

This mark 52 is provided at a position within a defined range on all types of wafers 12. Then, the distance from the mark 52 to the center of the boundary of the chip, the distance from the mark 52 to the bonding butt of the chip, the distance between the marks 52, the number of marks 52, the coordinates of each mark 52, and the distance from the mark 52 to the specific chip. The distance is determined in advance as a parameter. The wafer 12 is aligned based on these parameters, the shape of the mark 52, and the position of the mark 52.

A specific method of marking the mark 52 at a position within a defined range on wafers of different types will be described below.

FIG. 3 shows a marking method when the outer shape of the mark 52 and the outer shape of the chip 54 are the same. In this case wafer 12
The mark 52 may be marked on the chip 54 of the wafer 56 at a position corresponding to the position where the mark 52 is marked.

Further, FIG. 4 shows a marking method when the outer shape of the chip 58 is smaller than the outer shape of the mark 52. In this case, the marks 52 may be marked on several chips 58 of the wafer 60 at positions corresponding to the positions where the marks 52 on the wafer 12 are marked.

Furthermore, FIG. 5 shows a marking method when the outer shape of the chip 62 is larger than the mark 52. In this case wafer 1
The mark 52 may be marked on the corner of the chip 62 of the wafer 64 at a position corresponding to the position where the mark 52 of No. 2 is marked.

In this way, the same mark can be placed in the same position on the wafer even if the wafer type is different, so by registering the mark once, alignment can be achieved even on wafers of different types without having to register new patterns. It can be performed.

In the above embodiment, five marks 52 are provided on the wafer, but the present invention is not limited to this, as long as at least two marks 52 are provided at a predetermined interval.

Next, a method for aligning a marked wafer using the alignment apparatus according to the present invention will be described based on FIGS. 1 and 3.

(2): First, the shapes and marking positions of the marks 52, 52, etc. marked on the master wafer 56 placed on the work table 10 are registered as reference data using the microscope 2o of the alignment device.

■A new wafer 56 for secondary processing is placed on work table 1.
0, the microscope 20 is moved to the marking position of the mark 52 provided on the new wafer 56, and the image data or signal data of the mark 52 is taken into the current image frame memory 3o.

A comparator 34 compares the captured data and reference data.
The controller 38 moves the wafer 56 while making a comparison, searches for a position where the reference data and new data match, and stores the first position of the wafer 56 at that time.

(2) Next, move the microscope 20 to the marking position of the other mark 52 and repeat the above-described method at that position to create a new wafer 1 on which the registered data and new data match.
Store the second position of 2.

(2): Then, the wafer 56 is rotated from the first position stored in (2) and the second position stored in (2) so that the movement axis X-Y of the alignment device is aligned in parallel.

■: Repeat the steps from ■ to ■ below until the required accuracy is achieved to complete parallel alignment.

(2): After the parallel alignment of (2) is completed, the wafer 56 is moved based on parameters defined from position coordinates registered in advance. This completes the alignment of the wafer 12.

For the operations of ■ to ■, if necessary, move the X-Y moving mechanism 14 to 9.
This is also done with a coordinate system rotated by 0°.

〔Effect of the invention〕

According to the alignment method and apparatus according to the present invention, since a mark with a prescribed shape is provided at a prescribed position on the wafer, it is possible to align the wafer without registering a new pattern shape every time the type of wafer changes. can.

In addition, individual chips within the wafer can be positioned by detecting the coordinates of the marks, and processing using II mark data for positioning can be facilitated, greatly reducing misidentification of positioning. be able to.

[Brief explanation of the drawing]

′! Figure J1 is a block diagram showing a schematic structure of an alignment device according to the present invention, Figure 2 (A) is a plan view showing a state in which the alignment method and apparatus according to the present invention are marked on a wafer, and Figure 2 (B) 3 is an enlarged view of the alignment method and device according to the present invention, FIG. 3 is a plan view showing the alignment method and device according to the present invention in which the chip shape is marked in the same shape as the target, and FIG. 4 is an enlarged view of the alignment method and device according to the present invention. FIG. 5 is a plan view showing the alignment method according to the present invention and the device marking a chip shape smaller than the target shape; FIG. 5 shows the alignment method according to the present invention and the device marking a chip shape larger than the shape of the target. FIG. 10... Work table, 12.56.60.64... Wafer 14... X-Y axis drive mechanism, 16... Rotation drive mechanism, 20... Microscope, 28... Registration frame Memory, 30... Frame memory for current image, 34... Comparator, 38... Controller, 52
...Mark, 54.58.52...Chip.

Claims (2)

[Claims] (1) In an alignment method in which a part of a wafer having a pattern such as an IC on its surface is imaged and stored, and the wafer is aligned to a desired position based on the imaged and stored pattern, a specified shape is placed at a specified position on each wafer. An alignment method characterized by providing a mark, capturing and storing an image of the mark, and aligning a wafer based on the position and shape of the mark that is the same as the previously stored mark. (2) A wafer mounting means having an X-Y direction drive mechanism and a rotational direction drive mechanism; A storage means for storing photographed marks and a current image mark signal from the imaging means are inputted,
A matching unit that compares the current image mark with a previously stored mark and outputs a mark matching signal; and Control that outputs a drive signal that drives the mounting unit and aligns the wafer to a desired position based on the output of the matching unit. An alignment device comprising: means;