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.
