# Yield Development

| In the backbone part, there is a hypothetical yield over time curve, and some far-reaching conclusions are drawn form it.
|  | What do real yield curves look like? Well, few people know, because that is one of the bigger company secrets.
|  | However, in 2003, Leachman and Berglund, working for Sematech did a study and release some real (anonymous) data. Here is the interesting curve:
| The yield may go up somewhat faster than on the hypothetical curve, but several things are quit clear:
|  | Companies start production with yields as low as (10 - 20) %: In other words: Most of the chips produced go in the garbage bin!
|  | There is a lot frustration potential: For no recognizable reason your yield suddenly collapses substantially! (If the reason would have been recognizable, it would not have happened for more than a day or two and then not shown up on the monthly data given above!)
|  | It's rather difficult to have yields in excess of 80 % - and it is getting worse.

With frame

5.3.1 Moore's Law and what it Means

© H. Föll (Semiconductor Technology - Script)