Semiconductor Manufacturing Tour
Table of Contents
Slide 2 of 22
-
The wafer growing process is similar to crystal growing experiments that most of us did at school. A seed crystal of silicon is immersed in a bath of molten silicon. It is slowly pulled out, and because crystal growth occurs uniformly in all directions, the cross section is circular and, as it is pulled, it forms a cylindrical ingot of pure silicon. The ingot pulling process lasts for almost 24 hours and produces a cylinder of diameter larger than is desired. The ingot is ground down to the required diameter, and then is sliced into individual wafers.
-
At this stage, the wafers have a rough texture and need to be finely polished to meet the surface flatness and thickness specifications. To give you an idea of how critical the flatness specification is, consider the following analogy. If an airplane were to fly across the Pacific Ocean and hold its altitude to within 30 feet of the ocean surface, then this would be equivalent to the flatness specification of a wafer.
Return to the INFRASTRUCTURE Home Page