This guide is intended to provide an overview and basic introduction to SECS/GEM and its use in the semiconductor industry for beginners. AND IT IS NOT INTENDED to replace or serve as a complete reference to the standards. For a full reference to the standards, see SEMI.
SECS/GEM stands for SECS (SEMI Equipment Communication Standards) and the GEM (Generic Model for Manufacturing Equipment Communications and Control) standard is published and maintained by SEMI.org, an international organization of semiconductor manufacturers, is an organizing body that governs the standard for the manufacture of semiconductors.
To understand the SECS/GEM standards, you will need to purchase the following 3 basic SEMI standards:
- Standard SEMI E30 GEM – Defines the behaviors of the equipment (Business Rules), state machine and some rules such as which SECS-II messages should be used, in which situations and what should be the resulting activity.
- SEMI E5 SECS-II – Defines the details of the interpretation of messages (APIs) exchanged between computers and a host.
- SEMI E37 HSMS – High Speed SECS Messaging Services. This is a transport layer based on the TCP/IP protocol and a successor to the earlier SEMI E4 SECS-I standard which is based on serial communication.
The SECS/GEM interface was developed in the 1980s, but the concept of modern technology is very similar. As an illustration, consider web services technology. An enterprise application server uses the web service to interact with other services or hosts over HTTP or TCP/IP.
SEMI E30 STANDARD GEMA
The SECS/GEM standard defines a common set of equipment behavior and communication capabilities that provide the necessary functionality and flexibility to support the manufacturing automation programs of semiconductor device manufacturers. Equipment vendors may provide additional SECS-II functionality not included in GEM as long as the additional functionality does not conflict with any of the behaviors or capabilities defined in GEM. Such additions may include SECS-II messages, collection events, alarms, remote command codes, processing states, variable data elements (data values, state values, or hardware constants), or other functionality that is unique to a class. (engravers, climbers). , etc .) or specific instance of equipment.
Communication
The COMMUNICATION state model defines the behavior of the equipment in relation to the existence or absence of a communication link with the host. It also defines how communication with S1F13/S1F14 is established or restored when communication is interrupted.
control
The CONTROL state model defines the level of cooperation between the host and the computer. The CONTROL model provides the host with three basic levels of host control that determine the ability of the host to control the equipment:
- OFFLINE (Lower Level): Equipment operation is performed manually by the operator at the operator console. The host will respond with an SxF0 to any main message from the host that is not S1F13 or S1F17.
- ONLINE/LOCAL (mid-tier): In this state, the host can only perform “read-only” operations such as data collection. The host shall be prohibited from modifying any hardware constants that affect processes, remote commands that cause physical movement, or initiate processing.
- ONLINE/REMOTE (highest level): In this state, the host can operate the equipment as far as possible through the communication interface (“read-write” operations).
processing
The PROCESSING state model is highly dependent on the process, technology, and style of the equipment. However, it is expected that there are common aspects to these models.
remote command
The host can send a command to tell the computer to perform an automatic operation. For example: START, STOP, PAUSE, etc. This is similar to the manual operation performed by the operator at the console.
variables
The GEM standard defines three types of variables that can be accessed by the Host:
- State Variable: This is a “read-only” global variable defined on the computer. Whenever there is a processing, the equipment will update the respective status variable to reflect the latest data. Eg: incremental of some counter, current/previous state, etc.
- Equipment Constant: It is a global “read-write” variable defined in the equipment. The host can set or modify the team’s constant variable, which can affect the configuration which, in turn, changes the way the team behaves.
- Data Variable: This is a “local” variable that only exists in the collection event.
Data collection
SECS/GEM a couple of ways for the Host to collect data or information from the computer:
- A set of state variable values can be requested at any time using the S1F3 command.
- A set of equipment constant values can be requested at any time using S2F13
- The host can define a report that contains the state variable, the equipment constants, and the data variable, and then attach it to a collection event. When the device generates the event (through the S6F11 command), the report containing the values of these variables will be sent together.
- The host can define traces that will periodically sample state variable data.
- Another way is to take advantage of the alarm notification to collect more data with the collection event. As a rule, each time an alarm occurs or clears, an event (event collection) must be sent to the Host.
alarm notification
This function allows the Equipment to notify the Host every time an alarm/error occurs or is cleared in the equipment. Alarm refers to those occurrences that are abnormal, undesirable and endanger people, equipment or physical material in process.
Below are some of the characteristics of Alarm Management defined by GEM:
- Each alarm has two associated status models. ALARM SET (occurrence) and ALARM CLEAR (clear)
- Each AlarmSet and AlarmClear has an associated collection event. This is to address the host’s potential need for more extensive and flexible data reporting.
- The host can request which alarms will be enabled/disabled and the equipment will only notify the host about the enabled alarms.
Documentation
The SECS/GEM standard requires each team to provide a GEM Interface Reference Manual. Must include GEM compliance statement, full SECS-II message documentation, state model, list of state variables, equipment constants, data variables, alarms, collection events, etc. , which are defined/supported by the team.
