JP2012138548A - Substrate processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate processing method which can continue a processing operation by searching for an alignment mark in the case where the alignment mark cannot be detected due to deformation of a substrate.SOLUTION: When location information of a substrate is acquired based on an alignment mark image taken by a camera at an imaging reference position set for imaging an alignment mark but the alignment mark image is not detected by image taking at the imaging reference position, the alignment mark image is searched by moving the camera or a table so as to sequentially move an imaging position around the imaging reference position, and a position displacement amount between the imaging position and the imaging reference position when the alignment mark image is detected is calculated and a processing position by a processing tool is corrected.

Description

  The present invention relates to a method of performing substrate processing with a processing tool on the basis of an alignment mark attached to a substrate. The present invention is a substrate processing method particularly useful for a substrate that is easily distorted, such as a low-temperature fired ceramic (LTCC) substrate.

  For example, Patent Document 1 discloses a processing method of forming a scribe groove by rolling a glass substrate while pressing a cutter wheel (also referred to as a scribing wheel) on the surface of the substrate.

FIG. 5 is a perspective view showing an example of a conventional scribing apparatus. The scribing device 31 includes a table 32 on which the substrate W is placed. The table 32 can move in the Y direction along a horizontal rail 33 and is driven by a ball screw 35 that is rotated by a motor 34. The table 32 can be rotated in a horizontal plane by a drive unit 36 incorporating a motor.
A bridge 39 supported by support columns 37 erected on both sides of the table 32 supports a guide bar 38 extending in the X direction. The scribe head 41 is driven by a motor 42 and attached so as to be movable in the X direction along a guide groove 40 formed in the guide bar 38. The scribe head 41 is provided with a holder 42a, and a processing tool 43 (cutter wheel) is held by the holder 42a. The cutting tool 43 can adjust the cutting edge direction. Then, the processing tool 43 is lowered and the table 32 is moved in the Y direction with the cutting edge pressed against the substrate W, or the scribe head 41 is moved in the X direction along the guide groove 40, so that FIG. As shown in FIG. 4, the X-direction scribe grooves S _{1 and the} Y-direction scribe grooves S ₂ are formed in a lattice pattern on the substrate W.

A camera 44 is installed above the bridge 39, and the focus can be adjusted by moving up and down manually. An image captured by the camera 44 is displayed on the monitor 45.
An alignment mark (cross mark) for specifying the position is formed at the corner of the substrate W placed on the table 32, and an image of the substrate in the vicinity of the alignment mark is captured by the camera 44. Detect position. Specifically, alignment mark shape data (cross-shaped data) is stored in advance in the scribing device, and an alignment mark image is obtained by comparing the image of the substrate imaged by the camera 44 with the stored shape data. Is displayed in the image by pattern recognition. If it is determined that the alignment mark image is displayed, it is determined that the substrate is placed at the correct position, and the scribe head 41 is moved to a predetermined processing start position to start the scribe operation.
If the alignment mark image is not detected in the image, it is determined that the substrate is out of the correct position, and an error message is issued to urge correction of the substrate position. Thus, the operator manually adjusts the substrate position and corrects the positional deviation while checking the image captured by the camera 44 on the monitor 45.

  Further, in the scribing device 31 of FIG. 5, positioning reference pins 46 for guiding the substrate are provided so as to protrude from the table surface. By placing the end face of the substrate W in contact with the reference pin 46, the alignment mark of the substrate W is not greatly deviated from the imaging field range that can be projected by the camera 44.

Japanese Patent No. 3078668

However, when the substrate to be processed is an LTCC substrate, there are the following problems. The LTCC substrate is a substrate obtained by wiring conductors on a sheet in which an alumina aggregate and a glass compound are mixed to form a multilayer film, and firing the multilayer film at a temperature of typically 1000 ° C. or lower, for example, about 800 ° C. The alignment mark is formed before firing, but tends to be deformed and contracted as shown by the phantom lines in FIGS. 4A and 4B during firing. When the substrate is deformed, the position of the alignment mark A on the substrate is shifted from the originally designed position (design value). Therefore, if the substrate W is correctly placed at a position on the table where the alignment mark A should be projected within the imaging field of view of the camera, the alignment mark A will deviate from the imaging field of view of the camera due to the deformation of the substrate. As a result, it cannot be detected and an error is displayed.
In such a case, the substrate is manually moved to a position where an image of the alignment mark A can be detected. However, the position must be corrected by interrupting the automatic operation once, and the work becomes complicated. At the same time, time loss is large.

  On the other hand, if the placement position of the substrate W is guided by providing the positioning reference pins 46 on the table surface, the number of occurrences of error display can be reduced. In this case, the presence of the reference pins 46 is scribed. The moving range of the processing tool 43 to be used is limited, and there is a disadvantage that a processing area is limited.

Accordingly, an object of the present invention is to search for an alignment mark without interrupting the operation of the apparatus when the alignment mark cannot be detected due to deformation of the substrate, and to detect the image including the alignment mark and continue the processing operation. An object of the present invention is to provide a substrate processing method.
In addition, it occurs frequently when the positioning reference pin is not provided on the table, but the substrate processing that makes it easy to detect the alignment mark even when the substrate mounting position is slightly shifted. It aims to provide a method.

  The scribing method of the present invention made to solve the above-described problem is that a substrate with an alignment mark is placed on a table and imaged by a camera at an imaging reference position set for imaging the alignment mark. A substrate processing method in which position information of a substrate is acquired from an alignment mark image (an image including an alignment mark image), a processing position on the substrate is determined by a processing tool based on the position information, and then the substrate is processed. When the alignment mark image is not detected in imaging at the imaging reference position, the alignment mark image is searched by moving the imaging position to the periphery of the imaging reference position by moving the camera or table, and the alignment is performed. Calculates the amount of misalignment between the imaging position and the imaging reference position when a mark image is detected And it corrects the processing position by the processing tool Te.

In the method of the present invention, when the alignment mark cannot be detected at the imaging reference position due to the deformation of the substrate, the alignment mark image is searched by moving the imaging position sequentially around the imaging reference position by moving the camera or the table. To do. As a result, even if an alignment mark image cannot be detected in the imaging field range at the first imaging reference position, the camera or table is sequentially moved to the surrounding imaging position and searched for in the same imaging field range. Now that the image can be detected, the amount of misalignment between the imaging position and the imaging reference position when the alignment mark image can be detected is calculated, and the machining position by the machining tool is corrected based on this misalignment amount Thus, the substrate processing operation can be continued. This eliminates the complexity of manual work such as substrate position correction, and can reduce work time loss.
In addition, even if the alignment mark is slightly displaced from the photographing reference position, the alignment mark image can be detected, and the amount of deviation between the imaging position where the alignment mark image can be detected and the reference setting position is calculated. Since the processing position is determined by this, there is no need to provide a positioning reference pin on the table as in the past, and there is no interference between the reference pin and the processing tool, so the processing tool can be freely moved to the periphery of the board. There is an effect that it can be moved to.

(Means and effects for solving other problems)
In the above invention, when searching for an alignment mark image, it is preferable that the imaging position is sequentially moved in a spiral around the imaging reference position.
As a result, the alignment mark can be searched regardless of which direction the alignment mark has moved on the table.

In the above invention, the imaging field range at each imaging position by the camera may be circular or rectangular, and the imaging positions may be moved so that the imaging field ranges at adjacent imaging positions overlap each other at the peripheral portion of the field of view.
As a result, the alignment mark image can surely enter the imaging field of view at any of the adjacent imaging positions, so that detection failure can be eliminated.

In the above invention, it is preferable that the detectable region of the alignment image determined by the moving range of the imaging position of the camera and the imaging visual field range includes at least 5 mm in length and width with the imaging reference position as the center.
Since the substrate can be easily placed on the table with a positional accuracy of about 5 mm, the alignment mark can be reliably detected by setting at least 5 mm in the vertical and horizontal directions with the imaging reference position as the center. Therefore, alignment can be easily performed without a reference pin for positioning provided in a normal apparatus. Further, by making the reference pin unnecessary, inconveniences (interference with the scribe means, etc.) due to the reference pin can be prevented.

In the above invention, the substrate may be an LTCC substrate.
In the LTCC substrate, the alignment mark is deformed during firing, but the alignment mark can be easily detected even in that case.

It is a perspective view which shows an example of the scribing apparatus for enforcing one Example of the board | substrate processing method concerning this invention. It is the figure which showed an example of the moving order of the imaging position centering on the imaging reference position when searching an alignment mark image. It is a block diagram which shows the control system of the said scribe apparatus. It is a top view which shows the deformation | transformation state of a LTCC board | substrate. It is a perspective view which shows an example of the conventional scribe apparatus. It is a top view which shows the board | substrate scribed in the grid | lattice form.

In the following, the substrate processing method of the present invention will be described in detail based on an example of scribing an LTCC substrate.
FIG. 1 is a perspective view showing an example of a scribing apparatus for scribing an LTCC substrate. The scribing device 1 includes a table 2 that can fix and hold the LTCC substrate W by a suction mechanism (not shown). Table 2, are to be moved in the Y direction along the rails 3 by driving the ball screw 4 in the motor M _1. The table 2 can be rotated in a horizontal plane by a drive unit 5 with a built-in motor.

A bridge 8 supported by support columns 6 and 6 erected on both sides of the table 2 supports a guide bar 7 extending in the X direction. The scribe head 10 is driven by a motor M ₂ and can move in the X direction along a guide groove 9 formed in the guide bar 7.

  The scribe head 10 is provided with a holder 11. The holder 11 holds a dedicated cutter wheel (processing tool) 12 for scribing the substrate W. The cutter wheel 12 is configured such that the direction of the blade edge (the direction of travel relative to the substrate) can be adjusted in the X and Y directions. Then, by lowering the cutter wheel 12 and pressing the blade edge against the substrate W, the substrate W is transferred in the Y direction, or the scribe head 10 is moved in the X direction along the guide 7 to thereby move the X direction and the Y direction. Direction scribe grooves can be formed.

  The scribe head 10 is provided with a camera 13 that moves integrally with the cutter wheel 12. The focus can be adjusted by moving the camera 13 up and down. The distance between the camera 13 and the cutter wheel 12 is measured in advance, and the position in the image projected by the camera 13 and the position of the cutter wheel 12 are associated one-to-one. Image data picked up by the camera 13 is displayed on the monitor 14 and output to an image processing unit 21 (see FIG. 3) described later.

  An alignment mark A (see FIG. 4) for specifying the position of the substrate W is provided at the corner of the substrate W placed on the table 2, and the substrate W (alignment mark A is attached by the camera 13. An image including an alignment mark image (referred to as an alignment mark image) is detected by capturing an image of the vicinity), and thereby the position of the alignment mark A on the substrate W is detected. Specifically, a process for extracting the pattern of the alignment mark A is performed from the captured image by the image processing unit 21 of the control system 20 described later, and the pattern is compared with the shape data (cross mark) stored in advance. By doing so, the position of the alignment mark A is detected.

The camera 13 (and the scribe head 10) has a reference origin position, and when the position of the alignment mark A of the substrate W placed on the table 2 is detected, the motors M ₁ and M ₂ are driven. To return to the origin position, and to take an image at the origin position. Since the position of the camera 13 in the state of returning to the origin is the first imaging position in the operation of searching for the alignment mark A, this is set as the “imaging reference position”.

  FIG. 3 is a block diagram showing the control system 20 of the scribe device 1. The image data signal output from the camera 13 is given to the control unit 22 as image data for alignment mark collation via the image processing unit 21. The input unit 23 is an input device that can input various processing programs such as a scribing operation of the substrate W, and also has a search program used for detecting the position of the alignment mark. The control unit 22 is connected to an X direction motor drive unit 24, a Y direction motor drive unit 25, a table rotation motor drive unit 26, a scribe head drive unit 27, and a data holding area 28 (memory). In the data holding area 28, shape data (cross data) necessary for alignment mark matching by pattern recognition is stored in association with position detection together with various processing programs.

  The control unit 22 controls the position of the table 2 in the rotation axis direction based on the processing program input in advance from the input unit 23 and the setting parameter data necessary for the scribe operation, and moves the scribe head 10 in the X direction. Controls the movement of the table 2 in the Y direction. Also, when the scribing is performed by the cutter wheel 12, the cutter wheel 12 is controlled so as to press the surface of the substrate W with an appropriate load.

  Further, when searching for the alignment mark A with respect to the substrate W, an operation for collating the alignment mark shape data stored in the data holding area 28 with the image extracted by the image processing unit 21 is performed.

  Next, an alignment mark search operation performed by the control unit 22 will be described. The position detection tolerance can be arbitrarily changed as a parameter of the control program of the apparatus. However, in this embodiment, the position detection tolerance is 1 mm, and the imaging field of view of the camera 13 is the camera magnification (70 ×). Therefore, it is determined as a square region having a side of 2 mm. That is, if the center position of the alignment mark (the center of the cross mark) is projected within the imaging field of view when the substrate is projected at a certain imaging position, it is determined that the alignment mark A has been detected at that imaging position. To do.

  First, the substrate W is imaged by the camera 13 that has been returned to the origin position. At this time, the camera 13 is imaging a square area whose imaging field range is 2 mm in diameter at the imaging reference position. The image captured by the camera 13 and the alignment mark shape data stored in the data holding area 28 are collated, and the image of the alignment mark A is recognized in the image and the center of the mark is within the imaging visual field range. If it is, it is determined that the alignment mark A has been detected, and it is determined that the position of the substrate W is within an allowable error at the imaging reference position. Then, the scribing operation is started by moving the cutter wheel 12 (processing tool) to a preset predetermined processing start position.

  If the image of the alignment mark A is not projected within the imaging visual field range at the imaging reference position or the center of the mark is out of the imaging visual field range, it is determined that the image is out of the reference setting position. In that case, the camera 13 or the table 2 can be arbitrarily set as a parameter of the control program of the drive unit from the imaging reference position to the periphery thereof via the X direction motor drive unit 24 and the Y direction motor drive unit 25. However, it is usually set arbitrarily in consideration of the relationship between the size of the alignment mark and the imaging field of view of the camera, and in this embodiment, it is moved by about 1.8 mm, for example. The reason why the movement pitch is made shorter than the diameter (2 mm) of the imaging visual field range is to search for the alignment mark image while the peripheral portion of the imaging visual field range overlaps the visual field range at the previous imaging position.

  FIG. 2 is a diagram showing the movement order (search order) of the imaging position with respect to the substrate W by the camera 13, and the numbers (1) to (25) given in FIG. 2 (a) indicate the search order. The imaging field-of-view range of the camera 13 is a square area with a side of 2 mm, and the number (1) at the center is defined as the “imaging reference position” that is the first imaging position. This imaging reference position is the origin position of the camera 13 as described above.

When the substrate W is imaged at the imaging reference position (number (1)), if the alignment mark image is not in the imaging visual field range and the alignment mark image is not detected, the camera 13 or the table 2 is used to move the imaging position to the left. Move in the direction by 1 pitch (1.8 mm) and move to number (2). Thereafter, until the alignment mark image is detected, as shown by the arrow in FIG. 2B, the periphery is moved spirally around the imaging reference position (number (1)), and (1) → ( 2) Move the imaging position in the order of (3) (25).
For example, when an alignment mark image is detected at the imaging position of number (20), the control unit 22 calculates the total amount of positional deviation from the imaging reference position (number (1)) to number (20). The calculation result is used for automatic correction of the processing start position of the cutter wheel 12, and the scribing operation is started by moving the cutter wheel 12 to the corrected processing start position.

  As described above, even when the alignment mark image should be detected by imaging at the imaging reference position, even when the alignment mark image cannot be detected due to deformation of the substrate W or the like, the operation of the apparatus is automatically performed without interruption. Therefore, the scribing operation can be continued by searching and detecting the alignment mark image, thereby eliminating the troublesome work of correcting the position of the substrate W and the loss of work time.

  In addition, even when the alignment mark image cannot be detected at the imaging reference position, the search is performed by sequentially moving the imaging position in a predetermined pitch and in a predetermined movement order so that the alignment mark image can be detected. There is no need to place the substrate accurately by providing positioning reference pins on the table as in the prior art. Therefore, there is no possibility that the positioning reference pin and the scribe head 10 collide, and the scribe head 10 can be freely moved to the periphery of the substrate W.

  In the present embodiment, the range to be searched by moving the imaging position is limited to 5 mm in length and width so that if there is an alignment mark in the range, it can be surely found, but if the search time may be lengthened, This search area may be extended over a wide range. Further, although the movement pitch for one search is about 1.8 mm according to the control parameters of the control program, the pitch may be adjusted according to the allowable error. At this time, it is preferable that a part of the previous imaging visual field range overlap so as to eliminate the blind spot area where the alignment mark cannot be detected. In this embodiment, the imaging field of view is a square area, but it may be circular. In the case of a square, it is easy to eliminate the blind spot area.

  The search for the alignment mark image by the camera 13 includes an area of 5 mm in length and width, but within this range, the alignment mark shift due to deformation of the LTCC substrate can be sufficiently covered.

  In the above embodiment, the camera 13 is integrally attached to the scribe head 10, but may be attached to the bridge 8. It is only necessary that the positional relationship between the camera 13 and the processing tool 12 can be associated with one to one.

  As mentioned above, although the typical Example of this invention was described, this invention is not necessarily limited only to said Example. For example, as a substrate to be processed, in addition to a LTCC substrate that is easily distorted, it can be applied to a brittle material substrate such as a glass substrate, a semiconductor substrate, or a thin film solar cell substrate. In addition to the cutter wheel, the processing tool 12 attached to the scribe head 11 may be a fixed blade having directionality at the cutting edge. When performing laser scribing, the laser beam is condensed. An optical tool including an optical system for irradiating the substrate after forming a beam spot may be used.

  The present invention can be applied to a substrate processing apparatus such as a scribe apparatus that forms a scribe groove on a substrate such as an LTCC substrate.

A alignment mark W substrate 1 scribing device 2 table 13 camera 20 control system 22 control unit

Claims (5)

A substrate with an alignment mark is placed on a table, and positional information of the substrate is acquired from an alignment mark image captured by a camera at an imaging reference position set for imaging the alignment mark. A substrate processing method for processing the substrate after determining a processing position on the substrate based on a processing tool,
When the alignment mark image is not detected in the imaging at the imaging reference position, the alignment mark image is moved so that the imaging position is sequentially moved around the imaging reference position by moving the camera or the table. A substrate processing method characterized by searching and correcting a processing position by the processing tool by calculating a positional deviation amount between an imaging position and an imaging reference position when the alignment mark image is detected.   The substrate processing method according to claim 1, wherein when searching for the alignment mark image, the imaging position is sequentially moved in a spiral around the imaging reference position.   The imaging field range at each imaging position by the camera is circular or rectangular, and the imaging position is moved so that the imaging field ranges of adjacent imaging positions overlap each other at the peripheral part of the field of view. The board | substrate processing method of description.   The substrate according to any one of claims 1 to 3, wherein the detectable region of the alignment image determined by the moving range of the imaging position of the camera and the imaging visual field range includes at least 5 mm in length and width with the imaging reference position as a center. Processing method. The substrate processing method according to claim 1, wherein the substrate is an LTCC substrate.

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