JP2005052955A - Surface grinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface grinder which detects a change in sharpness of a whetstone and measuring the change in sharpness when working conditions are the same, and changing a posture of a whetstone spindle axis or a work spindle axis corresponding to the measured change so as to obtain a targeted shape. <P>SOLUTION: The surface grinder is provided with a tilter 3 for changing the posture of the whetstone spindle axis 2 and a tilter 31 for changing the posture of the work spindle axis 7. A displacement meter 6 for monitoring displacement of the whetstone spindle 2 while working is built into a whetstone spindle 12. The posture of the whetstone spindle axis 2 or the work spindle axis 7 is changed by using the respective tilters 3 and 31 based on determination of a threshold (variation per time) of a displacement table 20 of the axis 2. An information processor 15 keeps its state when a targeted workpiece shape is obtained, otherwise interrupts the working as the sharpness of the whetstone is regarded to have changed, and sharpens and corrects the whetstone. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a surface grinding apparatus, and more particularly to a surface grinding apparatus for obtaining a highly accurate shape by tilting and fixing a tilting posture of a grindstone and a workpiece in a surface grinding of a semiconductor wafer or the like with a minute and high precision.

Conventionally, the surface of a semiconductor wafer cut into a thin piece by a slicing machine is ground by a surface grinding apparatus as a post process. This surface grinding apparatus supports a semiconductor wafer on a chuck table, adjusts the parallelism between the wafer surface and the grindstone, then rotates the grindstone and presses the grindstone against the wafer surface to grind the wafer surface. . In Patent Document 1, the thickness of at least three points having different radii of a wafer that is a workpiece being ground is measured, and the shape is estimated. A surface grinding apparatus that controls the posture of a grindstone axis or a workpiece axis by a tilt mechanism is described.
Japanese Patent No. 3166146 FIG.

  However, in the conventional surface grinding apparatus that controls the attitude of the grindstone axis or the workpiece axis as shown in Patent Document 1, it is presumed that the grindstone performs the described function when the grindstone has a constant sharpness. Since the sharpness changes with machining, without knowing the situation, simply measure the thickness of the wafer at three points, estimate the shape, and adjust the posture of the grindstone axis or workpiece axis so that it becomes the target wafer shape Since the tool is forced to change, it may force the tool to be pressed, and naturally, normal grinding cannot be expected, the target wafer shape cannot be obtained, and depending on the control method, the worst wafer or tool may be damaged. Will be invited.

  The object of the present invention is to grasp the change of the sharpness of the grindstone when the processing conditions are the same, measure the change of the sharpness, and correspondingly adjust the wafer spindle axis or the work spindle axis so that the target wafer shape is obtained. Surface grinding device that can change the posture, does not forcibly press a tool that cannot be cut, does not cause damage to the wafer that is the tool or workpiece, can expect normal grinding, and can expect the target wafer shape Is to provide.

  Therefore, the present invention provides a displacement meter for monitoring the displacement of a grinding wheel spindle shaft during processing in a surface grinding apparatus provided with a grinding wheel spindle tilt device or / and a work spindle tilt device for changing the attitude of a grinding wheel spindle or / and a work spindle. Is incorporated in the grindstone spindle, the grinding process status is read from the monitor, and when it is judged that the grindstone can be cut, the attitude of the grindstone spindle axis and / or the work spindle axis is changed using each tilt device. When it is judged that the grindstone is not cut, the problem of the conventional product described above is provided by providing a surface grinding apparatus characterized by interrupting the processing and sharpening and correcting the grindstone. Settled.

  With such a configuration, the surface grinding apparatus of the present invention has a built-in displacement meter for monitoring the displacement of the grinding wheel spindle shaft being processed in the grinding wheel spindle shaft, and the target wafer corresponding to the monitored displacement of the grinding wheel spindle shaft. Change the attitude of the grindstone spindle or workpiece spindle axis using each tilt device so that the shape becomes the shape, and when the target wafer shape is obtained, the changed state is maintained and the target wafer shape is not obtained. In some cases, the processing was interrupted because the sharpness of the grinding wheel changed, and the grinding stone was sharpened and corrected, so that the tool that was not cut was not forced and the wafer that was the tool or workpiece could be damaged. Therefore, it is possible to expect a normal grinding process and to provide a surface grinding apparatus which can expect a target wafer shape.

  Preferably, the grinding load at the time of machining is read from the monitored displacement of the grinding wheel spindle axis during the machining, and the posture of the grinding wheel spindle axis or the work spindle axis changed by using each tilt device is maintained, or The processing may be interrupted and the grinding wheel may be sharpened, corrected, or the like may be determined based on a threshold value (amount of change per hour) of a previously provided grinding wheel spindle shaft displacement table.

  An example of the best mode for carrying out the present invention will be described with reference to FIG. FIG. 1 is a principal front schematic block diagram showing a surface grinding apparatus which is an example of the best mode for carrying out the present invention. In this surface grinding apparatus 1, a plurality of grinding wheel spindle shaft tilting devices 3 that change the posture of the grinding wheel spindle shaft 2 are attached to a spindle shaft support column 4 and a grinding wheel spindle 12 with both ends fixed. The tilt device 3 may use a known device such as a piezoelectric element. A displacement meter 6 for monitoring the displacement of the grinding wheel spindle shaft 2 during processing is built in the grinding wheel spindle 12 to prevent disturbances such as distortion. A plurality of work spindle shaft tilt devices 31 (the work spindle shaft tilt device 31 may be omitted) for changing the posture of the work spindle shaft 7 are fixedly attached to the table 9 and the work spindle 8 respectively. Yes. Reference numeral 5 denotes a cup grindstone fixed to the end of the grindstone spindle shaft 2, and 13 denotes a work fixed to the vacuum chuck 10 secured to the tip of the work spindle shaft 7.

A signal line 14 from each displacement meter 6 is input to the information processing device 15. The information processing device 15 is connected to each tilt control device 17 by a plurality of signal line bundles 16, and each tilt control device 17 is connected to the signal line 18. Each grindstone spindle axis tilt device 3 is connected to each work spindle axis tilt device 31 by a signal line 19. The information processing device 15 reads the grinding load at the time of processing from the displacement of the grinding wheel spindle shaft 2 being processed monitored by each displacement meter 6. The information processing device 15 of the displacement meter 6 uses the tilt devices 3 and 31. The changed grinding wheel spindle shaft 2 or workpiece spindle shaft 7 is held, or the processing is interrupted and the grinding wheel 5 is sharpened, corrected, etc., or the grinding wheel previously provided in the information processing apparatus 15 The determination is made based on the threshold value (change amount per time) of the spindle axis displacement table 20. The grinding wheel spindle is determined based on the threshold value of the grinding wheel spindle shaft displacement table 20 so that the target wafer shape can be obtained in accordance with the displacement of the grinding wheel spindle shaft 2 being processed by monitoring the displacement of the grinding wheel spindle shaft 2 being processed. The posture of the shaft 2 or the work spindle shaft 7 is changed by using the tilt devices 3 and 31, and when the threshold value of the displacement table 20 is a threshold value which becomes a target wafer shape, the changed state is maintained, and the displacement table When the threshold value of 20 is a threshold value that does not become the target wafer shape, the processing is interrupted on the assumption that the sharpness of the grindstone 5 has changed, and the sharpening, correction, etc. of the grindstone 5 are performed. (After changing the attitude of the grinding wheel spindle shaft 2 or the workpiece spindle shaft 7 by using the tilt devices 3 and 31, when the wafer as a workpiece is measured and becomes the target wafer shape, the changed state If the wafer shape is not maintained and the target wafer shape is not obtained, processing may be interrupted on the assumption that the sharpness of the grindstone 5 has changed, and the grindstone 5 may be sharpened, corrected, etc.)
[Effect of Best Embodiment of the Present Invention]
As described above, in the best embodiment of the present invention, a displacement meter for monitoring the displacement of the grinding wheel spindle shaft during machining is incorporated in the grinding wheel spindle shaft, and it corresponds to the monitored displacement of the grinding wheel spindle shaft during machining. By changing the attitude of the grindstone spindle or workpiece spindle axis using the tilt devices, so that the target wafer shape is obtained, the changed state is maintained when the target wafer shape is obtained. If the shape of the grinding wheel has not changed, it is assumed that the sharpness of the grindstone has changed, and the grinding stone is sharpened and corrected. Therefore, it is possible to provide a surface grinding apparatus that can be expected to achieve normal grinding and a desired wafer shape.

  Preferably, the grinding load at the time of machining is read from the monitored displacement of the grinding wheel spindle axis during the machining, and the posture of the grinding wheel spindle axis or the work spindle axis changed by using each tilt device is maintained, or The processing may be interrupted to sharpen or correct the grindstone, or may be determined based on a threshold value (amount of change per hour) of the displacement table of the grindstone spindle shaft provided in advance in the information processing apparatus 15.

It is a principal part schematic front block diagram which shows the surface grinding apparatus which is an example of the best form for implementing this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface grinding machine 2 Grinding wheel spindle axis 3 Grinding wheel spindle axis tilting device 5 Cup grinding wheel 6 Displacement meter 7 Work spindle axis 8 Work spindle 12 Grinding wheel spindle 13 Workpiece
15 Information processing device 17 Tilt control device 31 Work spindle axis tilt device

Claims (2)

In a surface grinding machine equipped with a grinding wheel spindle tilt device or / and a work spindle tilt device that changes the posture of the grinding wheel spindle and / or work spindle, a displacement meter that monitors the displacement of the grinding wheel spindle shaft during processing is built in the grinding wheel spindle. When the grinding process status is read from the monitor and it is judged that the grinding wheel can be cut, the attitude of the grinding wheel spindle shaft and / or the work spindle shaft is changed using the tilt devices, and the grinding wheel cannot be cut. A surface grinding apparatus characterized in that when the situation is judged, the processing is interrupted and the grinding wheel is sharpened and corrected. The grinding load at the time of machining is read from the monitored displacement of the grinding wheel spindle axis during machining, and the attitude of the grinding wheel spindle axis or workpiece spindle axis changed by using each tilt device is maintained, or machining is interrupted. 2. The surface grinding according to claim 1, wherein the grinding wheel is sharpened, corrected, etc., or determined by a threshold value (amount of change per hour) of a displacement table of a grinding wheel spindle shaft provided in advance. apparatus.

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