Semi E88

SEMI E88 defines the Stocker Specific Equipment Model (SEM) — the GEM-based state/event model that lets a host communicate with an AMHS stocker (the automated storage buffer itself) through the same standardized framework it uses for interbay/intrabay vehicles under E82's IBSEM, rather than treating stocker status as a vendor-specific interface. E85 already standardized the physical interface between a vehicle and a stocker's storage ports, but E85 says nothing about how a host software system queries or receives events from the stocker's own control system — slot occupancy, retrieval requests, fault states — and E88 is that missing data/communication layer, the stocker's equivalent of what E82's IBSEM already does for interbay and intrabay vehicles.

AMHS stocker holds dozens to hundreds of FOUPs in storage racks
Physical interface to vehicles already standardized by E85
SEMI E88 — Stocker SEM behavior modelGEM-based state/event model for the storage buffer itself
Slot occupancy and carrier-location reporting
Which slot holds which carrier, in standard GEM terms
Retrieval request and fault-state handling
Host can request a carrier or be notified of a stocker fault
Host manages any compliant stocker through one standard interface
Same GEM framework already used for vehicles and tools

The reason the stocker needed its own SEM rather than being folded into E82's IBSEM is that a stocker's relevant state is fundamentally about storage-slot inventory and retrieval logic, not vehicle motion and routing — a stocker doesn't move, it holds, and the events a host needs from it (slot occupancy changed, retrieval completed, a specific bay faulted) describe a different kind of behavior than IBSEM's vehicle-motion states. Without E88, a host tracking real-time WIP location across a fab would have a visibility gap at exactly the point where lots spend the most buffer time — inside the stocker — forcing either a proprietary integration per stocker vendor or an approximate, non-real-time view of storage inventory, which is the gap E88 closes by giving stockers their own GEM-compliant behavior model alongside E82's vehicle model and E85's physical hand-off spec.

SEMI E88 — Three AMHS Standards, Three Jobs vehicle behavior, physical hand-off, and now storage behavior E82 — IBSEM Vehicle motion, routing states E85 — Hand-off Physical vehicle-to- stocker port geometry E88 — Stocker SEM Slot occupancy, retrieval, fault states Three distinct standards cover vehicle, interface, and storage no single spec could have covered all three without conflating them

E88 closes the last visibility gap in a fab's AMHS stack: with E82, E85, and E88 together, a host can see a lot's complete journey — vehicle state, the physical hand-off, and buffer-time inside a stocker — through one consistent GEM framework instead of three different integration paths per vendor.

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