circuits are fabricated on
defect free and uniform crystal structure
as well as high chemical purity. These substrates are
processed in the form of
so the fabrication of circuits on these wafers is known as
steps needed to obtain wafers for circuit fabrication are very
complex, but these can be simplified as follows:
a type of sand that's used as raw material for wafers, undergoes a
refining process to become electronic grade
The EGS material is then used to grow single crystal ultrapure silicon
ingots either by the
Float Zone (FZ) method.
ingot then undergoes
to yield many wafers.
Example of a Czochralski Silicon Crystal Growing Furnace
wafer has to meet certain quality criteria or specifications for it to
be ready for wafer fabrication.
Electrical specifications include
the conductivity type (p or n), resistivity range, radial resistivity
gradient, and resistivity variations.
Mechanical specifications include
the diameter, thickness, total thickness variation (TTV), bow, warp,
flat dimensions, chips, indents, edge contour, bulk structural defects,
and surface orientation.
include oxygen content, carbon content, and
specifications include flatness, particle density, haze, saucer pits,
and other surface attributes.
Example of an ingot slicer
Photo of a finished wafer
Single Crystal Growth;
Wafer Cleaning; Crystal
Manufacturing; Wafer Fab Equipment
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