JP2012190987A - Method of displaying workpiece cutting line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it easier to intuitively recognize a cutting line position in a workpiece, such as a semiconductor wafer, thereby surely confirming the cutting line position without confusion.SOLUTION: An image processing apparatus 28 creates images whose corresponding relationship with control axis coordinates of a machine tool is known, the images being a wide range image showing the whole workpiece taken with a first camera 22, and a high magnification image showing in enlarged dimension a part of the workpiece taken with a second camera 24. The image processing apparatus creates plot data of cutting lines on the basis of cutting position data of the workpiece stored in a controller of the machine tool, and a display device 30 superimposes and displays the cutting lines on the wide range image and the high magnification image of the workpiece.

Description

  The present invention relates to a work cutting line display method, and more particularly to a work cutting line display method in which, for example, when a semiconductor wafer is diced, a cutting line is overlaid on an observation image of a semiconductor wafer.

  When a semiconductor chip is cut out from a thin workpiece such as a semiconductor wafer using a machine tool such as a slicer, it is cut along a cutting line. This cutting line must pass through a region between the circuit patterns at a predetermined position and a width of several tens to several hundreds of microns so as not to damage the circuits formed on the wafer.

  When setting up such a cutting line, in the process of cutting a single type of semiconductor wafer in large quantities, the semiconductor wafer is photographed with a camera, and the image is processed by a computer to automatically detect the position of the cutting line. However, automating input to the control device is performed (for example, Patent Document 1).

  On the other hand, in the case of high-mix low-volume production, it has also been conventionally performed to teach a cutting position for each workpiece to a machine tool control device by manual operation. In this case, after inputting the position information of the cutting line to the control device, it is necessary to check whether the cutting line is set without error before and after the processing. This is because, in the case of workpieces produced in a variety of small quantities, the workpieces are often expensive or prototypes that do not work as substitutes, and there are many cases where failure is not allowed.

  Here, FIG. 10 shows an image obtained by photographing a semiconductor wafer with a work observation camera mounted on a machine tool. 2. Description of the Related Art Conventionally, a machine tool such as a slicer that cuts a semiconductor chip from a semiconductor wafer is equipped with a camera having a lens with a high magnification, and a camera image can be displayed on a liquid crystal display or the like. The surface of the workpiece can be discussed on the spot as follows.

  In FIG. 10, reference numerals 2a to 2d indicate regions where circuit patterns are formed. Reference numeral 4 indicates a flat region where no circuit pattern is formed. The cutting line is set at the center of the flat region 4.

  In order to confirm the cutting line, first, the control axis is moved to the teaching position of the cutting line stored in the control device. As shown in FIG. 10, if the cross line 6 displayed at the center of the screen and the center position of the flat area 4 to be cut overlap, the cutting line is correctly set.

JP-A-6-122296

  However, the camera image displayed on the screen is only a small part of the workpiece to be cut. Normally, more than a dozen cutting lines are set vertically and horizontally on a single semiconductor wafer, and on a wafer with a large number of circuit patterns that look the same in appearance, an image with a narrow field of view is being viewed. The work is confusing without knowing where the wafer is.

  Further, in the image displayed on the screen, the cutting line is not actually displayed, but only the position to be cut is displayed at the center of the screen. When the planned cutting position overlaps with the crosshair 6 displayed in the center of the screen, it is difficult to get a real sense that the cutting line is set correctly, and there is a problem that it will be uncertain whether it will be cut at this position. .

  Therefore, an object of the present invention is to solve the problems of the prior art, make it easy to intuitively recognize the position of the cutting line on a workpiece such as a semiconductor wafer, and do not confuse confirmation of the position of the cutting line. It is an object of the present invention to provide a method for displaying a workpiece cutting line that can be reliably performed.

  In order to achieve the above object, the present invention provides a work cutting line display method for displaying a cutting line indicating a scheduled cutting position of a thin workpiece to be cut by a machine tool on an image taken by a camera for observing the workpiece. The first camera having a low-power lens and the second camera having a high-power lens are installed in the machine tool as the camera for observing the work, and a wide range image showing the entire work photographed by the first camera And an image processing device that generates a high-magnification image that projects a part of the workpiece photographed by the second camera and that has a known correspondence relationship with the control axis coordinates of the machine tool. The image processing device generates cutting line drawing data based on the workpiece cutting position data stored in the control device, and The superposed cutting line in the image and the high magnification image is characterized in that displayed on the display device.

It is a side view of the machine tool to which the display method of the present invention work cutting line is applied. It is explanatory drawing of the image which image | photographed the semiconductor wafer which is a workpiece | work with the low magnification camera. It is explanatory drawing of the image which displayed the cutting line on the wide range image of the workpiece | work of FIG. It is explanatory drawing of the image which overlapped and displayed the cutting line on the high magnification image of the semiconductor wafer which is a workpiece | work. It is explanatory drawing of the image which accumulated and displayed the cutting line on the thickness of the cutting groove width on the high magnification image of the semiconductor wafer which is a workpiece | work. It is a back explanatory drawing of the image which displayed the label which shows a position with a cutting line on the high magnification image of a semiconductor wafer. It is explanatory drawing of the image which displayed the label which shows the position confirmed by the high-magnification image to the wide range image of the semiconductor wafer. It is explanatory drawing of the image which overlapped and displayed the whole arrangement | positioning image of the cutting line on the high magnification image of the semiconductor wafer. It is explanatory drawing of the image of the other example which overlapped and displayed the whole arrangement | positioning image of the cutting line on the high magnification image of the semiconductor wafer. It is explanatory drawing of the image which image | photographed the semiconductor wafer with the high magnification camera by the conventional system.

  Hereinafter, an embodiment of a method for displaying a workpiece cutting line according to the present invention will be described with reference to the accompanying drawings.

First Embodiment FIG. 1 shows a machine tool to which a method for displaying a workpiece cutting line according to the present embodiment is applied. In FIG. 1, reference numeral 10 indicates a bed. A saddle 11 is movably installed on the bed 10 along a Y-axis guide 12. The saddle 11 is provided with a column 13. A Z-axis guide 14 is provided on the side surface of the column 13. The lifting platform 15 is guided by the Z-axis guide 14 and can be moved up and down, and a spindle head 17 is mounted horizontally. A disc-shaped diamond blade 19 is held on a grindstone shaft of the spindle head 17 via a grindstone holder 18.

  The bed 10 is provided with an X-axis guide 20 extending in a direction perpendicular to the Y-axis guide 12, and the working table 21 is provided with a turning table 23 having a turning axis C-axis. A work 40 to be processed is placed on the turning table 23. The workpiece 40 of this embodiment is a semiconductor wafer on which an electronic circuit has been formed, and is cut with a diamond blade 19 into semiconductor chips. Reference numeral 26 is a control device that numerically controls the control axis X-axis, Y-axis, Z-axis, and C-axis.

  In this embodiment, as a photographing means for observing the surface of the workpiece 40, the first camera 22 having a low magnification lens and the second camera 24 having a high magnification lens are combined, and the spindle head is interposed via an attachment member. 17 is mounted. Image data captured by the first camera 22 and the second camera 24 is output to a computer 28 linked to the control device 26. In the computer 28, image processing is executed by software, and an image of the work 40 is displayed on the display device 30. In this embodiment, a computer separate from the control device 26 is used for image processing. However, the image processing may be performed by a computer incorporated in the control device 26.

  Hereinafter, the procedure of the method for displaying a workpiece cutting line according to the present embodiment will be described in order.

  First, of the two cameras, the work 40 on the turntable 23 is photographed using the first camera 22 having a low magnification lens.

  FIG. 2 shows an image of a semiconductor wafer that is the workpiece 40 to be cut. A region indicated by a rectangular portion 12 is a region where a circuit pattern is formed. The white background is a portion where no circuit pattern is formed. The cutting line for cutting out the semiconductor chip is set to a white background that runs vertically and horizontally.

  Since the low-magnification first camera 22 is fixed to the machine tool, it is known by the image processing program executed by the computer 28 which position of the control axis coordinates (X axis, Y axis) corresponds to which part of the image. Is created.

  However, when the distance between the low-magnification first camera 22 and the workpiece 40 is short, the captured image of the workpiece 40 is distorted. Therefore, processing for correcting image distortion is performed as follows.

Image correction Aside from the workpiece 40 to be actually processed, a dummy workpiece having a highly accurate cross pattern in which a plurality of lines intersect vertically and horizontally is prepared, and this dummy workpiece is placed on the turntable 23. Take a picture with the first camera 22 of low magnification. This dummy work image is sent to the computer 28. The computer 28 obtains data about how the image from the first camera 22 is distorted while comparing the position of the cross pattern on the image of the dummy work with the position on the actual dummy work. Then, using the distortion data, image processing for correcting an image obtained by photographing the workpiece is performed by the computer 28, and a low-magnification camera image is corrected to an image without distortion similar to that obtained from infinity. The corrected image data is stored in the storage device of the computer 28 and used to display a wide range image of the work 40.

Next, the cutting position to be the cutting line is taught to the control device 26 of the machine tool. The cutting line is taught while observing the workpiece 40 with an image taken by the second camera 24 having a high magnification lens. As shown in FIG. 10, the X axis and Y axis of the control axis are moved while operating the operation panel 42 so that the crossed line 6 displayed in the center of the screen matches the position to be cut. If the crosshair 6 is at the position to be cut, the operation panel 42 is operated to register that position as the cutting position. This operation is repeated to teach the control device 26 the positions of all the cutting lines.

  In this way, during the operation of teaching the position of the cutting line on the workpiece 40 to the control device 26, how the cutting line is registered in the image of the second camera 24 displayed on the display device 30. It is not displayed. Therefore, the work 40 is displayed over a wide range on the display device 30 using the image data that has been photographed by the first camera 22 having the above-described low-magnification lens and corrected to an image without distortion as follows. The cutting line registered in the control device 26 is displayed so as to be superimposed on the image.

  Therefore, FIG. 3 shows a wide range image of the workpiece 40 displayed with the cutting lines superimposed on the display device 30. 3, Lx1, Lx2, Lx3,... Indicate cutting lines extending in the X-axis direction, and Ly1, Ly2, Ly3,... Indicate cutting lines extending in the Y-axis direction.

  Cutting position data taught to the control device 26 is input to the computer 28. The computer 28 generates drawing data of a cutting line from the cutting position data, and displays it in a wide range image of the workpiece 40 shown in FIG. The images are displayed on the display device 30 in a superimposed manner.

Display of cutting width In the wide range image of the workpiece 40 shown in FIG. 3, the operator sees that thin lines Lx1, Lx2, Lx3,..., Ly1, Ly2, Ly3,. It is possible to roughly check the arrangement of the cutting line set on the workpiece by teaching. If there is a cutting line that is forgotten to be registered in the control device 26, it will not be displayed in the wide-range image, so that it can be seen at a glance.

  On the other hand, even if the arrangement of the entire cutting line is correct, it is not clear from the wide range image of FIG. 3 whether each cutting line is set correctly.

  When cutting semiconductor chips from a semiconductor wafer, the cutting line often has to pass through an allowable width of tens to hundreds of microns so as not to damage the electronic pattern on the wafer. In the wide-area image of the workpiece 40, it is impossible to confirm whether the cutting line is within this allowable width.

  Therefore, as shown in FIGS. 4A and 4B, the display device 30 is configured such that the cutting line is superimposed on the high-magnification image photographed by the second camera 24 having a high-magnification lens using the computer 28. To display.

  In FIG. 4 (a), w represents an allowable width through which the cutting line should pass. For example, the cutting line Ly4 passes through substantially the center of the allowable width w. As shown in this image, if the cutting line Ly4 passes through the center of the allowable width w, the circuit patterns arranged on both sides can be cut without being damaged. On the other hand, as shown in FIG. 4B, the cutting line Ly4 may be shifted to one side in the allowable width w. In this case, only by looking at this image, it is not sure whether the circuit pattern can be cut without damaging it when cut along the cutting line Ly4.

  Therefore, as shown in FIG. 5, it is preferable that the cutting line is overlaid on the high-magnification image of the workpiece 40 with a thick line corresponding to the width of the cutting groove that is actually formed when the diamond blade 19 is cut.

  In this embodiment, the workpiece 40 is cut in advance using the same type of diamond blade 19 and under the same processing conditions, the actual cutting width is measured, and the data is input to the computer 28 and registered. The computer 28 superimposes on the high-magnification image as shown in FIG. 5 with a thick line having a width in which the size of the cutting width correlates with the magnification of the high-magnification image.

  As shown in FIG. 5 (a), if the cutting line Lx4 is at the center of the allowable width w, the operator who sees it intuitively knows that the cutting line has been accurately set at a position that does not damage the circuit pattern. Can be confirmed.

  On the other hand, as shown in FIG. 5B, if the cutting line Lx4 is close to one side of the allowable width w and protrudes from the line that defines the allowable width, It is possible to intuitively understand that the cutting line is not set correctly.

  As in this embodiment, it is preferable that the cutting line drawn with a thick line on the high-magnification image is colored and drawn, or hatched or patterned to draw graphically so as to appeal visually. .

  In addition, when the control panel X and Y axes of the machine tool are moved by operating the operation panel 42, the second camera 24 is moved in accordance with the movement, and the portion displayed in the high magnification image is also moved. It looks as if there is a groove in that position. Compared with the conventional confirmation method, which has a poor sense for the operator, it can be confirmed with a specific image whether the cutting line has been set correctly.

As described above, in the wide-range image of the workpiece 40 shown in FIG. 3, the rough arrangement of the cutting line is confirmed, and in the high-magnification image shown in FIG. 5, whether the cutting line is set correctly. Suitable for checking. Since the image of the entire semiconductor wafer and its details are combined, the images are switched to each other as follows.

  In the wide range image of the workpiece 40 shown in FIG. 3, when an operator designates an arbitrary position to be confirmed by clicking with a pointing device such as a mouse, the position data is sent from the computer 28 to the control device 26. Since the control device 26 moves the control axis, the X axis, and the Y axis to designated positions, when the screen of the display device 30 is switched to a high-magnification image captured by the second camera 24, the screen of the display device 30 is displayed. Above, a high-magnification image of the workpiece 40 at the designated position is displayed. Thus, if an arbitrary position is designated on the wide-range image, the cutting line can be confirmed in the high-magnification image at that position.

  At this time, as shown in FIG. 6, a label A <b> 1 indicating the position is superimposed and displayed on the screen of the display device 30 displaying the high-magnification image. Further, the current position on the workpiece 40 displayed as a high-magnification image is stored in the storage device of the computer 28 every time the position is designated. As shown in FIG. 7, when a wide-range image of the workpiece 40 is displayed on the display device 30, all the positions that have been displayed as high-magnification images are displayed with labels. In this way, the position confirmed in the high-magnification image corresponds to the position in the entire work 40, and when the displayed label is clicked, the control axis, the X axis, and the Y axis move to that position, and the second Since the high-magnification image of the part is displayed by the camera 24, it is convenient for observing the same place over and over again, and the high-magnification image is not displayed by overlapping the same part. Efficiency can be lost.

Second Embodiment Next, a second embodiment of the workpiece cutting line display method according to the present invention will be described with reference to FIGS.

  In the first embodiment of the present invention described so far, in order to confirm the cutting line taught to the control device 26 before the workpiece 40 is machined with the machine tool, the cutting line is displayed on a wide range image or a high magnification image of the workpiece 40. Is an embodiment in which are displayed in an overlapping manner.

  When confirming the cut state after the processing of the workpiece 40 is finished, the details of the workpiece 40 are observed with a high-magnification image, and at the same time, the currently observed position is in any part of the entire workpiece 40. It is convenient if you can figure out if there is. Originally, the video of the first camera 22 and the video of the second camera 24 may be displayed on the display device 30 at the same time. However, there are cases where simultaneous display is not possible due to display resolution limitations.

  Therefore, in the second embodiment, the entire arrangement image of the cutting line that has been overlaid on the wide range image of the workpiece 40 is displayed overlaid on the high-magnification image as shown in FIG. In this case, the magnification is reduced and the high-magnification image is overwritten so that the entire arrangement image of the cutting line is displayed on the screen of the display device 30.

  Further, simply superimposing the entire arrangement image of the cutting line, it is not known which part of the workpiece 40 is the high-magnification image that is currently displayed. For example, as shown in FIG. A mark M to be displayed is displayed on the cutting line.

  Further, instead of displaying the mark indicating the current position, as shown in FIG. 9, the cutting line arrangement image is changed so that the center of the screen of the high magnification image matches the current position on the cutting line arrangement image. It may be displayed in a superimposed manner.

  As described above, according to the second embodiment, the details of the workpiece 40 are observed in the high-magnification image, and at the same time, it is intuitive to determine which portion of the entire workpiece 40 is currently observed. Therefore, it is possible to efficiently carry out the work of confirming the cut state of the finished workpiece.

  As mentioned above, although the preferred embodiment was mentioned and demonstrated about the display method of the workpiece cutting line by this invention, this invention is not limited to this embodiment, In addition to the dicing process of a semiconductor wafer, it is a glass substrate. It can be applied to various processing with a grindstone, such as when grooves are precisely machined.

DESCRIPTION OF SYMBOLS 10 ... Bed, 11 ... Saddle, 13 ... Column, 17 ... Spindle head, 18 ... Grinding wheel holder, 19 ... Diamond blade, 21 ... Processing table, 22 ... First camera, 23 ... Turning table, 24 ... Second camera , 26 ... Control device, 28 ... Computer, 30 ... Display device, 40 ... Workpiece

Claims (10)

In the work cutting line display method for displaying a cutting line indicating a cutting position of a thin workpiece to be cut by a machine tool on an image taken by a camera for observing the workpiece,
A first camera having a low-power lens and a second camera having a high-power lens are installed in the machine tool as cameras for observing the workpiece,
A wide-range image that reflects the entire workpiece photographed by the first camera and a high-magnification image that magnifies and projects a part of the workpiece photographed by the second camera, having a correspondence relationship with the control axis coordinates of the machine tool A known image is generated by an image processing device,
Drawing data of a cutting line is generated by the image processing device based on the cutting position data of the workpiece stored in the control device of the machine tool, and the cutting line is superimposed on a wide range image and a high magnification image of the workpiece. And displaying on a display device a workpiece cutting line display method.   In the high-magnification image of the workpiece, the cutting line is visually drawn by applying a pattern to a thick line having a thickness corresponding to the width of a cutting groove formed when the workpiece is cut by the width of the grinding wheel or the grinding stone. The display method of the workpiece cutting line of Claim 1 characterized by the above-mentioned.   In advance, a dummy work depicting a highly accurate intersection pattern is photographed by the first camera, the position of the dummy work on the image is compared with the actual position of the dummy work, and the image of the first camera is displayed. The work cutting line display method according to claim 1, wherein data on how to be distorted is obtained in advance, and a wide range image of the work by the first camera is corrected based on the distortion data.   On the screen of the display device that displays a wide range image of the work, an arbitrary position on the wide range image is designated using a pointing device, a control axis is moved to the designated position, and the display device is 4. The method for displaying a workpiece cutting line according to claim 1, wherein a high-magnification image is displayed by the second camera. Store the current position on the work displayed in the high magnification image,
4. The display according to claim 1, wherein when the wide-range image is displayed on the display device, a display of a position currently displayed as a high-magnification image is superimposed on the wide-range image and displayed. 5. How to display the workpiece cutting line.   All the positions on the workpiece displayed as high-magnification images on the display device are stored, and when displaying the wide-range image on the mud spray device, all the indications indicating the positions displayed so far in the high-magnification image are displayed. The work cutting line display method according to claim 5, wherein the work cutting line is displayed on the wide range image.   7. The workpiece according to claim 6, wherein the display of the position is designated by a pointing device, the control axis is moved to the designated position, and a high-magnification image by a second camera is displayed on the display device. How to display the cutting line. When displaying a high-magnification image on the display device,
2. The display device according to claim 1, wherein the cutting line arrangement image is displayed with a lower magnification so that the entire cutting line arrangement image can be displayed on the high magnification image screen. To display the workpiece cutting line.   9. The workpiece cutting line display method according to claim 8, wherein a current position on the workpiece displayed in the high-magnification image is displayed in the cutting line arrangement image.   9. The method for displaying a workpiece cutting line according to claim 8, wherein the center of the screen displayed as the high-magnification image and the current position on the arrangement display image of the cutting line are displayed so as to coincide with each other. .

Images