SECS – Data Collection and Communications
With the growing need for semiconductor manufacturing systems to receive information from, and to communicate with, the processing and metrology tools in the fabrication process, it has become essential to have comprehensive data acquisition and communications capabilities in place that facilitate real-time automated information exchange. The value of the manufactured products and the costs of producing and operating a semiconductor manufacturing facility have risen tremendously. Losses due to tool unavailability and down time are significant. Progress has been made to maximize capital utilization by improving overall equipment efficiency. To collect equipment status, availability, and performance data automatically, the equipment must be capable of reporting changes in state, using event messages and equipment variables.
The automation of this information exchange offers significant support to:
- Achievement of reliability goals
- Improved process performance (reduce excursions)
- Accelerated tool qualifications
- Maximized productivity
Facilitated by Semiconductor Industry Communications Standards
SEMI, (Semiconductor Equipment and Materials Industry), a semiconductor industry organization, has developed communications standards that facilitate the needed communications between the fab host computer and the equipment that serves the manufacturing and development environments.
The SEMI Standards Program covers most aspects of semiconductor process equipment and materials. Compliance to the specific SEMI Equipment Communications Standards protocols (SECS), enables standardized communications between fab host computers and semiconductor manufacturing equipment. SECS is a standardized SEMI specified communications protocol.
Put very simply SECS is a protocol to transmit data and control messages in a platform-independent manner containing message codes that are agreed to by all vendors in the industry.
- SEMI E4 Protocol – a point-to-point communications protocol designed for factory automation messaging that uses low-speed RS-232 links. SECS-II messages sent using E4 are segmented into a sequence of 254 byte packets, each starting with a 10 byte header. The E4 protocol provides automatic error checking and retry capability. E4 messaging is used to transmit and reliably deliver E5 compliant data messages.
- SEMI E37 Protocol – a SEMI specified communications protocol designed for factory automation messaging that uses high-speed, Ethernet-based TCP/IP communications. The E37 protocol is also referred to as HSMS (High Speed Message Service) and was developed as a higher bandwidth replacement for E4. It also is primarily used to reliably deliver E5 compliant data messages. An E37 link is a higher performance alternative used in place of E4.
- SEMI E5 Message Data Protocol – a SEMI specified data messaging protocol designed for factory automation that typically uses either E4 or E37 as a link layer protocol. E5 defines platform-independent numeric, Boolean, and printable character data types, along with a standard format for representing these in its message layout. Data items can be scalars, vectors, or sequences (list) of any basic type. There are many predefined messages and application-specific data-types provided in the E5 standard.
SEMI Communications Standards facilitate communications between fab host computers and/or semiconductor manufacturing equipment, enabling:
- Product tracking
- Remote e-diagnostics
- Automated equipment and process control
- Failure detection
- Equipment performance tracking
- Logistics management