Dicing Saws Cut Chips To Size With Precision

2007-03-08 10:33:40

( Games-Toys )



Dicing saws are used to cut wafers. Although the process flow is simple, the tolerances required and the sensitivity of the materials for dicing make close monitoring necessary.

The primary parameters you monitor in wafer dicing are the rotating speed of the dicing saws, the feed rate through the dicing saws, the type of dicing saws used, the wafer material and wafer thickness.

Dicing machines are fitted with dicing saws that cut the silicon wafers. Typical dicing saws have blades impregnated with diamond composites or carbide grit. Alternatively, you may see laser beams used for dicing in lieu of dicing saws.

Dicing saws rotate at high speeds of several thousand revolutions per minute. The blades engage the silicon wafers at feed rates of about a centimeter per second.

You will observe some variation at this step in the process. Some processes practice dicing through in one pass of the wafer; others do a step-cut. Step-cutting means that dicing saws cut only part of the wafer in the first pass and only a second cut will separate the chips.

Another way is to have the second cut done by a second blade, where you have two dicing saws deployed in a two-spindle system, or by the same dicing saw in a second pass.

The wafer is held down on to a sticky tape, and the dicing is performed along a narrow gap usually fifty microns wide. The spaces between the chips, called dicing streets, are the channels through which the dicing saws should cut. If the dicing saws veer away from that path, you could destroy some of the circuitry and lose valuable chips.

The dicing saws are cooled with de-ionized water during the dicing. You must ensure the dicing is done carefully as it can cause back-side chipping which may affect the later mechanical quality of the chip.


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