Out of specification, a result beyond the USL or LSL. Unlike an OOC, an OOS is a product problem: the material must be dispositioned by scrap, rework, sorting or an approved deviation. In regulated pharmaceutical work an OOS result opens a formal investigation that has to rule out laboratory error before any retest result can be used.
Two wafers OOS on sheet resistance, the rest of the lot is in spec. Scrap those two and send the lot on with a note.
Also heard as
- out of spec
- out of specification
- nonconforming
Related terms
OOC
Out of control: shorthand for a point or chart that has violated a control limit or run rule.
Specification limits
Acceptance boundaries for a product characteristic set by design or customer requirements, labeled USL and LSL.
Opening the spec
Widening a specification limit so more product passes, instead of fixing the process that makes it.
Acceptance sampling
Accepting or rejecting a whole lot based on inspecting a random sample from it against a predefined plan.