SECS/GEM, the communication interface protocol for communication between semiconductor equipment and fab host. Fab host is a software application that is controlling and monitoring equipment processing using SECS/GEM protocol. SECS/GEM complaint equipment can communicate with the fab host using either TCP/IP (using SEMI standards E37 and E37.1 – HSMS) or RS-232 (using SEMI standard E4 – SECS-I). The SECS/GEM standard interface is used to start as well as stop equipment processing, collect measurement data, select recipes for products and change variables. With SECS (SEMI Equipment Communications Standard)/GEM (Generic Equipment Model), all this can be performed in a standard way. SECS/GEM protocol has been standardized by the non-profit association SEMI (Semiconductor Equipment and Materials International). Check www.SEMI.org to learn more about SEMI standards and SECS/GEM protocol.
In simple words, the SECS/GEM standard defines messages, state machines and scenarios to enable factory host applications to control as well as monitor manufacturing equipment. GEM standard is officially designated as SEMI standard E30, but frequently referred to as the GEM or SECS/GEM standard. The GEM is beneficial for both device manufacturers and equipment suppliers as it defines common set of equipment behavior and communication capabilities to provide functionality as well as flexibility to support manufacturing. Since GEM standard has only a few semiconductor-specific features, it has been adopted by other manufacturing industries as well, such as PV.
Among the capabilities offered by the SECS/GEM standard is –
- For fab host to start and stop processing
- For fab host to select, download and upload recipes from/to the equipment
- For fab host to query the equipment for values of various process parameters and equipment configuration
- For fab host to set equipment configuration parameter values
- For equipment to send alarms to the fab host
- For fab host to define reports of various variables and associate them with events such as lot start or wafer complete
- For equipment to send various events and associated reports to the fab host
Since SECS/GEM is a communication protocol, it is platform and technology as well as programming language independent. The host side of a connection is executing on a computer system provided by the factory, and the equipment side of a connection is running on a controller computer provided by the equipment manufacturer. This gives both – the fab as well as the equipment manufacturer interoperability, flexibility and platform independence. Both, the fab and the OEM can develop their software application without having to worry about communication compatibility, as long as both of them are adhering to SECS/GEM standards.
EINNOSYS Inc offers software solutions for both – the FABs to integrate with FAB host as well as for the OEMs to integrate with their controller software. By integrating EIGEM – Einnosys SECS/GEM software, the equipment or fab host becomes SECS/GEM capable without having to learn the details of various SEMI standards.
SECS describe the communication between a host computer and the equipment using a single connection. In the original concept and even today in the most common scenario, the equipment provides a single SECS interface for exclusive use by a single host. The message types defined by SECS are partially asymmetric – some message types are defined only for host use, others are defined only for equipment, but also many of them are defined for the same use by either side.
However, there is provision in the SECS standards for sharing a connection by specifying the device identification value in each message. The practice of connection sharing is not recommended for new deployments. It is a common practice that a connection is maintained for long periods of time and only interrupted if the equipment or host is rebooted. SECS connections are light weight and don’t use much network bandwidth. It is possible to run several SECS connections on a typical desktop computer.