Wafer Scrap Console

Of all the ways a fab loses money, scrap is the most visceral: a whole wafer, fully paid for in silicon and process time, thrown away before it ever yields a single sellable die. Unlike ordinary die-yield loss — where a wafer still produces some good chips — a scrapped wafer produces nothing, which makes it the most expensive kind of loss per event and the one operations watches most nervously.

The arithmetic is brutal at the leading edge. When a finished wafer costs fifteen to twenty thousand dollars, even a few percent scrap on a busy line is hundreds of wafers and millions of dollars every month. That's why turning a scrap rate into a currency figure, as this console does, changes the conversation — a "half a percent" improvement becomes a seven-figure annual number that funds the process control to achieve it.

Not all scrap is final. Some defects are reworkable: strip and redo a step rather than discard the wafer. But rework only makes sense when it costs less than the wafer value it recovers — a genuine economic decision, not a reflex. This calculator prices that decision explicitly, comparing the rework cost to the recoverable value and reporting the savings when rework wins, so containment teams can choose with the numbers in front of them.

The largest scrap events are excursions — a tool drifting out of control, scrapping whole lots until caught. This is precisely why fabs pour investment into statistical process control and inline metrology: the financial return is the scrap those systems prevent, which the excursion preset here makes concrete. Attack the root causes upstream in the Defect Density and Process Capability consoles, and price the silicon itself in the Wafer Cost console.