Why use Interface A (EDA) instead of SECS/GEM for data gathering?
This is a common question that the semiconductor manufacturing community continues to ask the experts at Cimetrix. Below is a comparison between the two standards and the data collection benefits of implementing the SEMI Interface A standards. Of course, SECS/GEM has its merits as well. However, they are not listed here.
- SECS GEM vs. Interface A
- SECS GEM & Interface A Similarities
- Learn More about the Interface A Standards
- Learn more about the SEMI SECS GEM Standards
- Cimetrix's Interface A Solutions
- Cimetrix's SECS GEM Solutions
SECS GEM vs. Interface A
| SECS/GEM | Interface A |
|---|---|
| SECS/GEM can support only one client connection. IC Makers cannot run several data gathering applications at the same time without an infrastructure to share the data. | Interface A can support multiple concurrent clients. Independent clients can simultaneously use Interface A. |
| SECS/GEM is only partially self-describing and therefore relies on good documentation. IC Makers have complained that the documentation is often poorly maintained and poorly written. | Interface A is self-describing through the E125 standard's metadata including a listing and description of all available data. Inherently, it should be synchronized with the actual equipment configuration. |
| SECS/GEM data is relatively flat and unorganized. The IC Maker must study the documentation, hardware, software, and processing to understand how to organize the data. | Interface A presents the data in a hierarchy, organized by the major hardware components. |
| Data in a SECS/GEM message is highly structured and relatively inflexible. | Interface A uses XML; therefore the inherently design to accommodate additional metadata. |
| SECS/GEM is only used in a few industries; therefore there are a limited number of experts in the world. | SOAP/XML and HTTP are the backbone of most Internet and Intranet applications. There are many programmers worldwide that are familiar with this technology. |
| There are relatively few software packages in the world to deal with SECS/GEM technology; most are only known to the Semiconductor industry. | There are a tremendous number of software packages worldwide from many industries that can handle SOAL/XML and HTTP technology. |
| In most factories, the SECS/GEM interface is used for equipment configuration and control; therefore subject to extensive oversight and lengthy change procedures. It can take at least several weeks for any data collection changes to be implemented. | Interface A is independent of the GEM interface and therefore immediately available for the dynamic data collection needs of the process engineers. |
SECS GEM & Interface A Similarities
Interface A uses many of the same concepts as SECS/GEM. Here is a mapping between the similar concepts and technologies.
| SECS/GEM | Interface A |
|---|---|
| Status Variables, Equipment Constants, and Data Variables | Parameters |
| Alarms | Exceptions |
| Collection Events (S6,F11) | Events in DCP |
| E39 Objects | SEMIObjType and Instance IDs |
| Trace Data Collection | Traces in DCP |
| Reports | Data Collection Plans/Reports |
| State Machines | State Machines |
| Enable/Disable Collection Events | ActivatePlan/DeactivatePlan |
| Define & Link Reports (S2,F33 & S2,F35) | DefinePlan |
