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Typical wafer size for new factories
(2007) : 300 mm diameter, 775 µm thickness, flatness
in lower µm region |
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Chip size a few
cm2, much smaller if possible |
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Yield Y = most important parameter
in chip production = % of chips on a wafer that function (= can be sold). |
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Y = 29 % is a good value for
starting production |
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Chip making = running about 20
times (roughly!!) through "materials" - "structuring"
loop. |
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About 400 - 600 individual processing
steps (= in / out of special "machine") before chip is finished on
wafer |
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More than 30 processing steps for
packaging (after separation of chips by cutting) |
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Simple estimate: 99.9% perfection for each
processing step meansY < 70 %. |
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© H. Föll (Electronic Materials - Script)
