This is the key standard for efficient host-equipment communication. It provides a common set of equipment behavior and communication capabilities offering the functionality and flexibility that semiconductor fabs expect as well as state models.
Described state models:
- Communication state model: Defining equipment behavior in regard to connectivity status to host system
- Control state model: Defines access rights für operator and host systems depending on the status (Online-Remote/Online-Local/Offline)
- Equipment processing state model: Defines Processing States (e.g. “Idle”, “Executing” or “Pause”) with the respective equipment behavior
Further state models are limits monitoring and spooling.
Examples for capabilities:
- Remote control: Commands sent by host for process control and material movement.
- Variable types: Definition of constants (e.g. equipment constant and discrete variables as basic variable types that can be pulled by the host
- Process program management (recipes): Transfer equipment instructions, called recipes, between host and production equipment.
- Material movement: Material transfer between equipment, buffers or storage facilities performed by operators, AGV robots, tracks or fixed material handling systems with notification to host about appearance and removal
- Data collection: Different possibilities for the host to pull data and information
- Alarm management: Ability of equipment to inform host about alarm notifications regarding occurring alarms and alarm clearing
With these functionalities, GEM utilizes the previously in SEMI E5 (SECS-II) specified messages, streams and functions. Furthermore the SECS/GEM standard requires that semiconductor equipment suppliers provide a GEM documentation including messages and a compliance statement.