5.2.3 Summary to: Chips on Wafers

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

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© H. Föll (Electronic Materials - Script)