Semi E42

SEMI E42 defines Recipe Management, the standard model for how a host and equipment agree on what a "recipe" even is — a named, versioned set of process parameters — and how recipes get uploaded, verified, selected, and executed consistently across equipment from different vendors. Before E42, each vendor's tool stored and identified recipes its own way, which meant a host managing a fab full of mixed equipment had no reliable way to confirm "recipe X version 3" on one tool was the same parameter set as "recipe X version 3" on another, or even that a recipe selected by name hadn't silently drifted from what the host thought it uploaded.

E42's real contribution is making recipe identity verifiable rather than assumed: a host can query equipment for its current recipe inventory, confirm a specific recipe's version before dispatching a job against it, and detect if a recipe was edited locally on the tool outside the host's control — a scenario E42.1's SECS-II messages make into an explicit, checkable exchange instead of a silent trust assumption. This matters because recipe drift is one of the most dangerous classes of fab error: if an operator tweaks a recipe directly on the equipment console without updating the host's record, every downstream system that assumes "recipe X" still means what the host thinks it means is now wrong, and E42 gives the host a standard way to catch that mismatch before it reaches wafers rather than after a yield excursion traces back to it.

E42 completes the same GEM300 chain as E39 (object services), E40 (processing management), and E41 (exception management): a process job under E40 is only as trustworthy as the recipe E42 confirms it's actually running, and a recipe mismatch is exactly the class of abnormal condition E41's exception model is built to surface to the host.