Cutting blade detection mechanism for a cutting machine

#The present invention relates to a detection mechanism for detecting the standard position of the cutting direction of a cutting blade mounted to a cutting machine such as a dicing machine, or the time of exchanging the cutting blade and a chipped cutting blade.

#A semiconductor wafer or the like is generally cut by a precision cutting machine called “dicing machine”. The dicing machine cuts a workpiece of a semiconductor wafer or the like with a rotating cutting blade. This cutting blade is worn down by its use and its diameter decreases. In the dicing machine, therefore, the standard position of the cutting direction of the cutting blade needs to be adjusted to cope with a reduction in the diameter of the cutting blade and hence, it has a cutting blade detection mechanism for detecting the standard position. The dicing machine also has a cutting blade detection mechanism for detecting the time of exchanging the cutting blade whose diameter is reduced by abrasion and a chipped cutting blade.

#The above cutting blade detection mechanism comprises a blade passing gap into which the cutting blade passes, and a light emitting means and a light receiving means both of which face the blade passing gap. In this cutting blade detection mechanism, a light emitted by the light emitting means is received by the light receiving means and the state of the cutting blade located in the blade passing gap between the light emitting means and the light receiving means is detected by converting the amount of light received by the light receiving means into a voltage corresponding to the amount of light. The cutting blade detection mechanism for detecting the standard position of the cutting direction of the cutting blade is disposed on a workpiece holding means for holding a workpiece, and when the cutting blade is moved in a cutting direction so as to gradually pass into the blade passing gap and the voltage corresponding to the amount of light received by the light receiving means reaches a predetermined value, the standard position of the cutting direction of the cutting blade is determined. That is, when the cutting blade is caused to gradually pass into the blade passing gap, the amount of light received by the light receiving means gradually decreases and the value of voltage falls. When the value of voltage reaches a predetermined value, the standard position of the cutting direction of the cutting blade is determined as a position where the cutting blade comes in contact with the top surface of the workpiece holding means, for instance. Meanwhile, the cutting blade detection mechanism for detecting the time of exchanging the cutting blade and a chipped cutting blade is disposed on a spindle unit having the cutting blade. As the cutting blade is worn down, the amount of light intercepted by the cutting blade located between the light emitting means and the light receiving means decreases. In this case, the value of detection voltage gradually rises from the time when the cutting blade has been exchanged and it reaches a predetermined value, the cutting blade detection mechanism indicates the time of exchanging the cutting blade. Further, the above cutting blade detection mechanism judges occurrence of a chipped cutting blade and indicates the time of exchanging the cutting blade since it shows the voltage value exceeding a predetermined value intermittently when the cutting blade is chipped.

#FIG. 1 is a perspective view of a dicing machine which is a cutting machine having a cutting blade detection mechanism constituted according to the present invention;

#FIG. 2 is a perspective view of a main portion of the dicing machine shown in FIG. 1;

#FIG. 3 is an enlarged perspective view of a main portion of a spindle unit constituting the dicing machine shown in FIG. 1;

#A cutting blade detection mechanism for a cutting machine according to preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings hereinafter.

#FIG. 1 is a perspective view of a dicing machine equipped with the cutting blade detection mechanism of the present invention.

#The dicing machine shown in FIG. 1 has a substantially rectangular parallelepiped housing 10. As shown in FIG. 2, the housing 10 comprises a stationary base plate 2, a chuck table mechanism 3 disposed on the stationary base plate 2 movably in a direction indicated by an arrow X that is a feeding direction and holds a workpiece, a spindle support mechanism 4 disposed on the stationary base plate 2 movably in a direction indicated by an arrow Y that is an indexing direction (direction perpendicular to the direction indicated by the arrow X as the feeding direction), and a spindle unit 5 disposed on the spindle support mechanism 4 movably in a direction indicated by an arrow Z that is a cutting direction.