What-If Limits
What-if mode
Section titled “What-if mode”What-if mode lets you stage scenario limit changes without changing baseline lot data.
Those changes live in notebook state, so they can be saved, versioned, and reviewed later.
Where you can edit limits
Section titled “Where you can edit limits”Current alpha flows let you drive limit changes from:
- the CPK table
- scatter
- histogram
Review impact
Section titled “Review impact”Review impact compares baseline limits to the current proposal exactly on the server.
It is not a summed estimate. It uses the actual die fail sets, which means overlap between tests is handled correctly.
The review shows:
- before and after yield
- rescued dies
- newly failing dies
- per-test fail deltas
- most affected wafers
Export
Section titled “Export”The impact review can export CSV for external review.
Use the export when you need to:
- circulate a proposal outside the product
- keep an audit trail for a limit discussion
- compare multiple candidate proposals offline
Practical rule
Section titled “Practical rule”Do not argue from a dragged line alone.
Use impact review whenever a limit change might affect a real release or engineering decision.