secs/gem protocol

SECS/GEM is the communication standard between semiconductor equipment and fab host systems (MES), enabling automation, data collection, and remote control. Standards stack: (1) SECS-I (E4)—serial RS-232 physical layer (legacy); (2) HSMS (E37)—TCP/IP-based high-speed messaging (modern); (3) SECS-II (E5)—message format defining data structures; (4) GEM (E30)—state models, scenarios, and behavior for equipment. Key GEM capabilities: communication state model (online/offline), control state model (local/remote), processing state model (idle/executing), alarm management, remote commands, recipe management, material movement, data collection, clock synchronization. Message types: (1) Primary messages (S1-S20+)—initiated by host or equipment; (2) Secondary messages—replies. Common streams: S1 (equipment status), S2 (equipment control), S5 (alarms), S6 (data collection), S7 (recipe management), S14 (material movement). Interface A: product wafer tracking through equipment. Equipment Data Acquisition (EDA/E164): modern trace data interface for high-frequency sensor data. Implementation: equipment vendors provide SECS/GEM interface, fab integrates with MES. Critical for fab automation enabling: recipe download, lot tracking, process data collection, SPC, and automated fault detection—cornerstone of smart manufacturing.