MICROCHIP FABRICATION occurs as a cycle of steps carried out as many as 20 times.
Many chips are made simultaneously on a silicon wafer, to which has been applied
a light-sensitive coating.
(1). Each cycle starts with a different
pattern, which is projected repeatedly onto the wafer
(2). In each place
where the image falls, a chip is made. The photosensitive coating is removed
(3) ,and the light-exposed areas are etched by gases
(4). These areas are then
showered with ions (or "doped"), creating transistors
transistors are then connected as successive cycles add layers of metal and