Silicon is the crucial building block in the fabrication of
computer chips. Raw silicon is first extracted from common
sand. A series of chemical steps refine it until the purity level
reaches 99.9999999 percent. Thus, for every ten billion atoms,
only one non-silicon atom can be permitted. That is like one
tennis ball in a line of ping pong balls stretching from the earth
to the moon.
Silicon ingots are then "grown" from the purified molten silicon
and sliced into round wafers ranging from 150mm to 200mm
(6 to 8 inches) in diameter with a thickness about that of a
credit card.