Sunday, November 4, 2012

What is a metal spin or chip spin?

A silicon wafer is "photo-etched", where the masking needed to etch out the different layers to produce the desired circuitry pattern is placed upon to wafer by "projecting" the image on the wafer with light (like film photography), before being chemically processed to actually etch out the pattern. The light-sensitive chemical for the masking is placed on the wafer while it is spinning to produce a uniform coat.

Respins would be where this light sensitive material is reapplied to a previously processed wafer so a new masking can be applied and the wafer re-etched to correct bugs detected in the previous run.

That probably refers to "spin-coating", a method of adding layers to a wafer. In this, a wafer is fixed on a turntable, and the photochemically active lacquer is sprayed on it's surface. The wafer then is spinned at the necessary speed to evenly distribute the material to the desired thickness.
The layer is then exposed to light through a mask, and after that, the non-exposed parts of the layer are etched away. If a new layer has to be added, that is a respin.


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