Semi E99.1

SEMI E99.1 defines the SECS-I/SECS-II message set that carries SEMI E99's carrier-ID reader/writer data between equipment and host — E99 defines the mechanical and functional reliability requirements for the reader/writer hardware itself, while E99.1 defines the actual messages a tool sends to report a successful read (or a read failure) and, where supported, to confirm a write-back to the tag. Without E99.1, E99's hardware-reliability guarantees would be real at the reader itself but invisible to the host unless it polled or guessed — E99.1 is the protocol binding that turns a physical tag read into a timely, standardized message the host's carrier-management system (E87) can act on immediately, closing the same data-model-to-wire-protocol gap that E87.1, E90.1, E94.1, and E98.1 each close for their own parent standards.

SEMI E99 — reader/writer hardware reliability requirements
What the reader must physically guarantee at read time
SEMI E99.1 — SECS-I/SECS-II message bindingHow a successful or failed read actually reaches the host
Tool reports a successful tag read immediately
Standardized SECS-I/SECS-II event, not a delayed batch update
Tool reports a read failure or write-back confirmation
Host knows immediately when a read didn't succeed
E87 carrier management updates in real time, with failure visibility
Not silently trusting an assumed location

The reason this needed its own protocol spec rather than folding read events into a generic carrier-management message is that a read failure is operationally distinct from a successful read — a host that only hears about successful reads has no way to distinguish "this carrier isn't here" from "the reader failed to read a carrier that is here," and those two cases call for completely different responses (reroute a lot vs. troubleshoot a reader). E99.1 closes that gap by giving read failures their own standardized reporting path alongside successful reads, so a fab's carrier-management and maintenance systems both get the specific signal they each need, rather than a flat "carrier ID unknown" that could mean either and leaves the host guessing which problem it's actually looking at.

SEMI E99.1 — Success and Failure Need Different Signals a flat "ID unknown" leaves the host guessing which problem it has Successful read Standardized event, immediate Carrier management updates Read failure Its own standardized event Triggers maintenance, not routing Two distinct problems, two distinct standardized signals not one ambiguous "unknown" status

E99.1 completes the carrier-identification chain: E99 guarantees the reader hardware is reliable, and E99.1 guarantees that whatever the reader actually experienced — success or failure — reaches the host as a distinct, actionable signal rather than disappearing into an ambiguous status field.

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