Method and apparatus for cutting semiconductor wafers

A method of exchanging a blade of a multiple-blade semiconductor substrate saw which includes a used first blade and a second blade, the used first blade being carried on a first shaft for rotation with the first shaft and the second blade being carried on a second shaft for rotation with the second shaft, the method comprising:

• removing the used first blade from the first blade mount;
• mounting a new first blade on the first blade mount;
• rotating the new first blade in a first position;
• monitoring a distance from a first sensor to a face of the new first blade as the new first blade rotates in the first position, the first sensor being associated with the second shaft;
• indicating whether a first variance in the monitored distance as the new first blade is rotated is greater than a predetermined maximum first variance;
• and, if the first variance is not greater than the maximum first variance,
• contacting a semiconductor substrate with the new first blade and with the second blade.

A semiconductor wafer saw, comprising:

• a carrier for a microelectronic workpiece;
• a driver;
• a shaft coupled to the driver and extending opposite the carrier, the shaft having an axis;
• a blade mount carried by the shaft for rotation with the shaft;
• a blade carried by the blade mount for rotation with the blade mount, the blade having a face and a peripheral cutting edge;
• a sensor spaced from the blade and oriented toward the face of the blade, the sensor maintaining a fixed angular position with respect to the axis as the blade is rotated with the shaft, the sensor being adapted to measure a distance to the face of the blade;
• and
• a processor operatively coupled to the sensor, the processor being adapted to indicate if the distance to the face of the blade deviates more than a permitted deviation from a baseline distance to the face of the blade as the blade rotates.

A semiconductor wafer saw, comprising:

• a carrier for a microelectronic workpiece;
• a first spindle extending opposite the carrier, the first spindle having a first axis;
• a first blade carried by the first spindle for rotation with the first spindle, the first blade having a face and a peripheral cutting edge;
• a second spindle extending opposite the carrier, the second spindle having a second axis;
• a second blade carried by the second spindle for rotation with the second spindle, the second blade having a face and a peripheral cutting edge;
• a first sensor carried by the second spindle and adapted to measure a first distance to the face of the first blade, the first sensor maintaining a fixed angular position with respect to the first axis as the first blade rotates about the first axis;
• a second sensor carried by the first spindle and adapted to measure a second distance to the face of the second blade, the second sensor maintaining a fixed angular position with respect to the second axis as the second blade rotates about the second axis;
• and
• a processor operatively coupled to the first and second sensors, the processor being adapted to indicate if variation of the first distance as the first blade rotates exceeds a predetermined maximum first variation and to indicate if variation of the second distance as the second blade rotates exceeds a predetermined maximum second variation.