JPH09323320A - Method and apparatus for measuring groove shape of grooved roller for wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the accurate wear amount of a groove by measuring the groove shape under substantially the same conditions as those of a real apparatus without damaging the roller. SOLUTION: A measuring wire 27 having a diameter equal to that of the wire of a real apparatus is wrapped in the groove 15 of a grooved roller 14. Then, after the tension of the wire 27 is set by a spring, the groove wrapped with the wire 27 is imaged by a camera 20, and the video signal from the camera 20 is processed. Thereafter, the groove shape of the roller 14 is measured based on the profile data of the groove 15 of the roller 14 and wire 27 obtained by the processing. The tension of the wire 27 by the spring is set to the same as the tension of the wire of the real apparatus wrapped in the groove 14 of the roller 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring the groove shape of a grooved roller for a wire saw, which cuts a thin plate-shaped wafer with a traveling wire through a workpiece such as a cylindrical semiconductor ingot, ceramic, or glass. .

[0002]

2. Description of the Related Art A wire saw is one of the cutting devices for cutting a workpiece such as a semiconductor ingot, ceramic, glass or the like into a thin wafer. In this wire saw, a wire reeled out from one wire reel is wound around the grooves of a plurality of grooved rollers to form a wire row, and the wire row is wound on the other wire reel, and the wire row includes abrasive grains. By supplying a liquid and pressing the workpiece, the lapping action of the abrasive grains cuts the workpiece into a large number of wafers.

[0003] When the grooves of the grooved rollers are worn, the accuracy of the cut wafer is adversely affected. That is, when the inclined surface of the groove is worn, the wire moves in the axial direction of the grooved roller, and as a result, the thickness of the wafer becomes uneven. Further, when the groove is worn in the radial direction and the groove diameter between the adjacent groove and the groove greatly changes, the wire meanders, and as a result, the flatness of the wafer is deteriorated.

Therefore, conventionally, the groove shape of the grooved roller is measured using a shape measuring machine, and when the result is out of an allowable value, it is judged that the life of the grooved roller has expired, and the grooved roller is replaced with a new one. I am trying to do it. FIG. 6 is a cross-sectional view of essential parts showing a measuring state of the grooved roller 1. According to the figure, the stylus tip terminal 2 of the shape measuring machine is pressed against the groove 3 of the grooved roller 1 and is made to travel in the axial direction of the grooved roller 1 (the direction indicated by the arrow in the figure). Measure the shape. FIG. 7 is output data showing the measurement results. Based on this data, the pitch (P) between the adjacent grooves 3, 3, ... And the variation (α) in the groove diameter are calculated, and the grooves 3, 3 ,. The amount of wear is being measured.

[0005]

However, in the conventional shape measuring apparatus, since the stylus tip terminal 2 of the shape measuring machine is pressed against the grooved roller 1, the grooved roller 1 is damaged by the stylus tip terminal 2. However, there is a drawback that the grooved roller 1 is worn out early due to the influence of the scratches. Further, since the conventional shape measuring device measures the shape of the groove itself in which the wire is not wound, it cannot measure the groove shape in a loaded state. Therefore, the conventional device has a drawback in that the amount of wear of the groove 3 in a state where the wire is wound cannot be accurately measured.

For example, as shown in FIG. 7, both walls 3 of the groove 3 are formed.
If there is a difference between the inclination angles θ1 and θ2 of A and 3B, although the position of the wire wound around the groove 3 is actually deviated in the left-right direction in FIG. Is measured and P is calculated at this depth, so a measurement error occurs. Further, as shown in FIG. 6, when a crack 3C is formed in the deep portion of the groove 3, even though the wire wound around the groove 3 actually pushes the crack 3C and is displaced downward, Since the terminal 2 measures the deep portion of the groove 3 and calculates α at this deep portion, a measurement error occurs.

Such a problem can be solved by measuring on a real machine in which the wire is wound in the groove 3, but there is no space for arranging the shape measuring machine on the real machine, and if the space is to be secured, the entire wire saw Has the drawback of becoming large. The present invention has been made in view of the above circumstances, and provides a groove shape measuring method and device for a wire saw grooved roller that can measure the groove shape under substantially the same conditions as an actual machine without damaging the grooved roller. The purpose is to do.

[0008]

According to the present invention, in order to attain the above object, a wire fed from one wire reel is wound around grooves of a plurality of grooved rollers to form a wire row, and the other. The groove shape of the grooved roller for a wire saw for cutting the work into a number of wafers by winding the work around the wire reel and supplying a working liquid containing abrasive grains to the wire row and pressing the work. In the measurement method,
A measuring wire having a diameter equal to that of the wire is wound around the groove of the grooved roller with a predetermined tension, and then the groove around which the measuring wire is wound is imaged by an image pickup means, and a video signal from the image pickup means is taken. Image processing is performed, and the groove shape of the grooved roller is measured based on the contour data of the groove of the grooved roller and the measuring wire obtained by the image processing.

According to the present invention, first, the measuring wire having the same diameter as the wire of the actual machine is wound around the groove of the grooved roller with a predetermined tension. Next, the groove around which the measuring wire is wound is picked up by the image pickup means, and the video signal from the image pickup means is image-processed. Next, the groove shape of the grooved roller is measured based on the contour data of the groove of the grooved roller and the measuring wire obtained by image processing. Therefore, in the present invention, the groove shape can be measured under substantially the same conditions as the actual machine without damaging the grooved roller. In this case, if the tension of the measuring wire is set to be substantially the same as the tension of the wire of the actual machine wound around the groove of the grooved roller, the groove shape can be measured in a state closer to the actual machine.

In the present invention, the image pickup means and / or the grooved roller can be moved in the radial direction of the grooved roller by the radial direction moving means. Thus, according to the present invention, even with grooved rollers having different diameter sizes, the image pickup means and / or the grooved roller can be moved to a position where they can be picked up by the image pickup means. In the present invention, the imaging means and / or
Alternatively, the grooved roller can be moved in the axial direction of the grooved roller by the axial movement means. Accordingly, the present invention can continuously and efficiently measure the shape of the groove to be measured of the grooved roller in a short time.

In the present invention, the grooved roller can be rotated about the axis by the rotating means. With this, according to the present invention, it is possible to rotate the groove at the measurement target position to a position where the image can be captured by the image capturing unit.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a groove shape measuring method and device for a grooved roller for a wire saw according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a groove shape measuring device according to an embodiment of the present invention. On the measuring table 12 of the groove shape measuring apparatus 10 shown in the figure, a moving table 16 for supporting the grooved roller 14, a light source 18 for imaging the groove 15 of the grooved roller 14, and a camera 20.
And an imaging unit consisting of.

The moving table 16 constitutes a linear bearing together with the guide table 22 installed on the measuring table 12, and is driven by a driving force from a driving mechanism (not shown) in the X direction (horizontal direction) with respect to the guide table 22. Direction). The moving stroke of the moving table 16 is set to the length of substantially one grooved roller 14. A motor 24 and a bearing 26 are installed on the moving table 16.
The grooved roller 14 has a bearing portion 14A at one end thereof detachably connected to a spindle (not shown) of the motor 24,
The bearing portion 14B at the other end is rotatably supported by the bearing 26, and is supported so that its axial direction is parallel to the moving direction (X direction) of the moving table 16. Therefore, when the moving table 16 is moved, the grooved roller 14 is moved in the axial direction, and when the motor 24 is driven, the grooved roller 14 is rotationally driven about the shaft center.

By the way, as shown in FIG. 1, the grooved roller 14 has the measuring wire 2 in the grooves 15, 15 ...
7 and 27 are wound around each. The measuring wire 27 is made of the same material and has the same diameter as the actual wire. As shown in FIG. 2, the measuring wire 27 has a base end portion 27A fixed to the upper surface of the moving table 16 via a fixing jig 29, and three grooves 15, 15 at the same time.
The front end portion 27B is fixed to the upper surface of the moving table 16 via a spring 31 while being wound around each group. The measurement wire 27 is set to have the same tension as the tension of the wire of the actual machine wound around the groove 15 of the grooved roller 14 by the urging force of the spring 31.

On the other hand, the light source 18 and the camera 20 are fixed so as to face each other on the inner surface of a frame 28 formed in a gate shape. The frame 28 is provided so as to straddle the grooved roller 14. Therefore, when the grooved roller 14 is moved in the X direction, the grooved roller 14 moves in the inner space portion 3 of the frame 28.
While passing through 3, the light source 18 illuminates the light, and the projection light is imaged by the camera 20.

Further, the pair of columns 30, 30 includes the measuring table 1
It is erected on 2. The columns 30 and 30 are provided with leg portions 28A and 28A of the frame 28 so as to be movable in the Z direction (up and down direction) in the drawing via linear bearings (not shown). The lifting motors 32, 32 of the frame 28 are installed above the columns 30, 30, and these motors 32, 32 are controlled by a drive mechanism (not shown) so as to rotate in synchronization. Therefore, when the motors 32, 32 are driven, the frame 28
That is, the light source 18 and the camera 20 are moved in the vertical direction (the radial direction of the grooved roller 14), and the heights of the light source 18 and the camera 20 with respect to the grooved roller 14 are adjusted.

FIG. 3 is a block diagram showing a control circuit of the groove shape measuring apparatus 10. The control circuit is centrally controlled by a CPU 34, and the CPU 34 controls a position control unit 36 based on a command signal from an external operation unit (keyboard) 35 shown in FIG. The position control unit 36 uses the CP
Indexing rotation drive mechanism 38 based on the command signal from U34
Control. As a result, the rotation motor 24 for the grooved roller 14 is driven, and the rotational position of the grooved roller 14 is adjusted. The position control unit 36 also controls the Z-axis drive mechanism 40 based on a command signal from the CPU 34. As a result, the motors 32, 32 of the frame 28 are driven and the height of the image pickup unit is adjusted. Further, the position control unit 36
Controls the X-axis drive mechanism 42 based on a command signal from the CPU 34. As a result, the moving table 16 is driven and the grooved roller 14 is reciprocated in the X direction.

On the other hand, the image signal from the camera 20, namely, the groove 15 of the grooved roller 14 and the measuring wire 27 (see FIG. 3).
The image signal indicating (1) and (2) are output to the image processing device 44, where they are subjected to monochrome binarization processing. This binary signal is
It is stored in the image memory 43 that stores the binarized image data for one screen via the CPU 34. The CPU 34 uses the binarized image data stored in the image memory 43 to outline the contours of the groove 15 and the measuring wire 27, that is, the contours that form the contour of the groove 15 and the measuring wire 27 as shown in FIG. The position data on the XY coordinates of the point is obtained, and the pitch P of the groove 15, the variation α of the diameter, the groove 15 are calculated based on this position data.
The angles θ1 and θ2 of the inclined surfaces on both sides are calculated, and the calculated results are displayed on the display 45 together with the shapes of the groove 15 and the measuring wire 27, or printed by the printer 46 or the plotter 48.

Next, a measuring method by the groove shape measuring device 10 configured as described above will be described. First, the moving table 16 is moved to the position shown in FIG. 1, and the grooved roller 14 is supported on the moving table 16 at this position. Next, the grooved roller 14 is rotated by the motor 24 to position the grooves 15A, 15A ... Of the portion to be measured at the upper portion as shown in FIG. Next, after the measurement wires 27, 27 ... Are wound around the grooves 15, 15, ..., The tension is set by the spring 31 to the same tension as the wire of the actual machine. Then, the frame 28 is moved in the Z direction by the electric motors 32, 32, and the light source 18 and the camera 20 are positioned at positions where the grooves 15A, 15A ... And the measuring wire 27 can be photographed.
This completes the measurement preparation.

Then, the movable table 16 is moved in the X direction, and the light source 18 and the camera 20 are driven to start photographing the grooves 15A, 15A ... And the measuring wire 27. The image signals indicating the grooves 15A, 15A ... And the measurement wire 27 captured by the camera 20 are output to the image processing device 44 shown in FIG. Then, the CPU 34 obtains the position data on the XY coordinates of each contour point forming the contours of the groove 15A and the measuring wire 27 as shown in FIG. Then, the CPU 34 calculates the pitch P of the groove 15A, the diameter variation α, and the angles θ1 and θ2 of the inclined surfaces on both sides of the groove 15A based on the position data, and displays the calculation results on the display 45.

In the present embodiment, since the measurement wire 27 is wound around the groove 15 of the grooved roller 14 in the measurement result and the measurement result is obtained, the position data is the measurement wire 2
7 is output as data including a part of the peripheral portion, but the groove 14
Even if there is a difference in the inclination angles θ1 and θ2 of the two walls 15A and 15B of each of the two walls, and even if there is a crack 15C (see FIG. 4) in the deep portion of the groove 14, the actual wire wound around the groove 15 is The P and α values can be measured at the position. That is, the distance in the axial direction between the tops T and T of the data indicating the shape of the measuring wire 27 is taken as the P value, and the radial distance is taken as the α value.

Therefore, according to the present embodiment, compared with the conventional measuring method for measuring the actual groove shape, the pitch P and the groove diameter are set under substantially the same conditions as the actual machine without damaging the grooved roller 14. The variation α can be measured. Thereby, the wear amount of the groove 15 of the grooved roller 14 can be accurately measured. Further, in the present embodiment, the tension of the measuring wire 27 is applied to the groove 15 of the grooved roller 14 by the urging force of the spring 31.
It is set to the same tension as the wire of the actual machine that is wrapped around. Therefore, it is particularly effective when the grooved roller 14 is an elastic body that is elastically deformed by the tension of the wire, and in this case, the groove shape can be measured in a state closer to the actual machine.

In the present embodiment, the light source 18 and the camera 2
Since 0 is provided so as to be movable in the radial direction of the grooved roller 14,
Even with grooved rollers having different diameter sizes, the camera 20 can be moved to a position where an image can be picked up and positioned. The movement in the radial direction is not limited to the light source 18 and the camera 20 side, and the grooved roller 14 may be provided so as to be movable in the radial direction.

In the present embodiment, the grooved roller 14 is used.
Since the grooved roller 14 is provided so as to be movable in the axial direction by the axial length of, compared with the conventional device using the stylus tip terminal,
One measurement stroke can be long. Therefore, the shape of the groove to be measured of the grooved roller 14 can be efficiently measured in a short time. The movement in the axial direction is not limited to the grooved roller 14 side, and the light source 18 and the camera 20 side may be moved in the axial direction.

Further, in this embodiment, the grooved roller 14 is used.
Since it is rotatably provided around the axis, the groove 15 at the measurement target position can be rotated and positioned to a position where the camera 20 can capture an image. Therefore, it is possible to measure the groove shape at a desired position without detaching the grooved roller 14 from the moving table 16 each time. On the other hand, by using the present groove shape measuring device 10, it is possible to judge the life of the grooved roller 14 and the timing of maintenance inspection (reproduction processing).

In the determination method, first, the groove shape of the new grooved roller 14 is measured, and the initial data of the pitch P ₁ and the groove diameter variation α ₁ are stored. Next, the grooved roller 14 is mounted on an actual machine, and n pieces (for example, 10 pieces) of workpieces are processed.
The intermediate data of P ₂ and α ₂ after cutting is stored.
Then, from the initial data P ₁ , α ₁ to the intermediate data P ₂ , α
Subtract ₂ to obtain the amount of change in the nth line. On the basis of the amount of change, the amount of change per work piece is obtained, and it is predicted at which line maintenance and inspection will be required and at which line the end of life will be reached. That is, the specified value of the maintenance inspection time and the specified value of the life are set in advance, and when cutting of the number of workpieces expected to exceed these specified values is finished,
Perform maintenance or replace with a new one.

As a result, the life of the grooved roller 14 and the timing of maintenance inspection can be efficiently judged. Incidentally, if the intermediate data is obtained not only once but a plurality of times for every n lines, a statistical value of the change in the shape of the groove with respect to the number of cuts can be obtained. it can. If the change amount is abnormal, it is determined that an abnormality has occurred in the wire saw, and an abnormality diagnosis of the wire saw is performed. Thereby, the failure of the wire saw can be prevented.

[0028]

As described above, according to the groove shape measuring method and apparatus of the grooved roller for the wire saw according to the present invention,
A measuring wire having the same diameter as the wire of the actual machine is wound around the groove of the grooved roller with a predetermined tension, and the groove around which the measuring wire is wound is imaged by the image pickup means and a video signal from the image pickup means is imaged. Since the groove shape of the grooved roller is measured based on the contour data of the grooved roller and the measuring wire obtained by performing the image processing, the actual machine without damaging the grooved roller The groove shape can be measured under substantially the same conditions as. Therefore, the present invention can accurately measure the wear amount of the groove of the grooved roller.

[Brief description of drawings]

FIG. 1 is a perspective view of a groove shape measuring device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a measuring wire is stretched by a spring.

3 is a block diagram showing a control circuit of the groove shape measuring device shown in FIG.

FIG. 4 is an enlarged view of a main part showing a groove of a grooved roller and a measuring wire imaged by a camera.

FIG. 5 is an explanatory diagram for calculating a groove shape from position data.

FIG. 6 is an enlarged sectional view of an essential part showing a conventional groove shape measurement state.

FIG. 7 is an explanatory view showing output data of a conventional groove shape measurement result.

[Explanation of symbols]

 10 ... Groove shape measuring device 14 ... Grooved roller 15 ... Grooved roller groove 16 ... Moving table 18 ... Light source 20 ... Camera 27 ... Measuring wire 31 ... Spring 34 ... CPU 44 ... Image processing device

Claims (7)

[Claims] 1. A wire row is formed by winding a wire fed from one wire reel around the grooves of a plurality of grooved rollers, and is wound on the other wire reel, and the wire row contains abrasive grains. In the groove shape measuring method of the grooved roller for wire saw for cutting the workpiece into a large number of wafers by supplying the working liquid and pressing the workpiece, a measuring wire having a diameter equal to that of the wire is used. After being wound around the groove of the grooved roller with a predetermined tension, the groove around which the measuring wire is wound is imaged by the image pickup means, the image signal from the image pickup means is subjected to image processing, and the image processing is performed. A groove shape measuring method for a grooved roller for a wire saw, wherein the groove shape of the grooved roller is measured based on the obtained contour data of the groove of the grooved roller and the measuring wire. 2. A grooved roller for a wire saw according to claim 1, wherein the tension of the measuring wire is set to be substantially the same as the tension of the wire wound around the groove of the grooved roller. Groove shape measuring method. 3. A wire row is formed by winding a wire fed from one wire reel around the grooves of a plurality of grooved rollers, and is wound on the other wire reel, and the wire row contains abrasive grains. In a groove shape measuring device for a grooved roller for a wire saw, which cuts the work piece into a large number of wafers by supplying a working liquid and pressing the work piece, it is formed to have a diameter equal to that of the wire. A measuring wire wound around the groove of the grooved roller, a tension applying means for applying a tension to the measuring wire wound around the groove of the grooved roller, and the measuring wire in the groove of the grooved roller. Image pickup means for picking up an image of the groove in a wound state, image processing means for image-processing the video signal from the image pickup means, groove of a grooved roller obtained by image processing by the image processing means, and the measurement Groove shape measuring device wire saw grooved rollers, characterized in that it comprises a calculating means for calculating a groove shape on the basis of the contour data of the ear. 4. The tension of the measuring wire by the tension applying means is set to be substantially the same as the tension of the wire wound around the groove of the grooved roller. Groove shape measuring device for grooved roller for wire saw. 5. A grooved wire saw according to claim 3, further comprising radial moving means for moving the image pickup means and / or the grooved roller in a radial direction of the grooved roller. Roller groove shape measuring device. 6. A groove for a wire saw according to claim 3, further comprising axial moving means for moving the image pickup means and / or the grooved roller in an axial direction of the grooved roller. Roller groove shape measuring device. 7. A groove shape measuring device for a grooved roller for a wire saw according to claim 3, further comprising rotating means for rotating the grooved roller about an axis.