### 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 |  |
|  | 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 %. |

© H. Föll (Electronic Materials - Script)