Communications between factory host and production equipment
The SEMI E30 GEM standard describes how communications and control capabilities should be supported between a factory host (MES) and production equipment. Detailed scenarios outline the exact sequence and subset of SECS-II messages (as defined in the SEMI E5 standard) that should be used to accomplish a particular capability and what supporting tool data must be provided to the host. The intent is to collect enough information to give the host insight into how a tool is performing and sufficient supervisory control to remotely manage product processing, so that operator presence is not always required on the factory floor.
Enabling essential SECS/GEM communications
SECS/GEM capabilities start with the most basic requirement to establish a SECS communication channel between the factory host and the tool; the next step is to determine who is in control of the tool: the remote factory host or a local operator. Once the host has control, it can issue remote commands that the tool must execute – typically to initiate processing on the equipment, but sometimes to route material or perform pre- or post-conditioning activities. Material processing is accomplished by running Process Programs (recipes); while GEM mandates how recipes should be managed between the host and tool, the recipes themselves contain your equipment-specific processing instructions.
A core concept in GEM is the ability for the tool to provide useful information to the host:
- Status and Data Variables are used to report the tool’s current state, sensor readings, and processing results.
- Events are published whenever something noteworthy occurs on the tool.
- Alarms are raised whenever the tool has encountered an error condition.
The factory host can use this information to initiate processing requests, monitor results and adjust processing parameters as needed, or respond to abnormal scenarios, all using standard SECS messaging.
Equipment requirements for SEMI E30
Basic GEM compliance requires tools to implement a minimum subset of all the capabilities described in the E30 standard. Most SECS and GEM-based fabs expect a tool to at least implement remote control, data/event/alarm publication, and process program management. Some capabilities are less commonly requested, such as spooling (storing tool messages for later transmission, when communication between the host and tool is down) or limits monitoring (simple SPC-like analysis of process data reported by the equipment). Regardless of what a particular fab is requesting your tools support, our SECS/GEM connectivity products offer full compliance for every capability described in the SEMI E30 standard.