What is SECS/GEM?

1. SECS (SEMI Equipment Communication Standards) and GEM (Generic Model For Communications and Control Of Manufacturing Equipment) standard is published and maintained by SEMI.org, an international organization of semiconductor manufacturers, is an organization body that governs the standard for semiconductor manufacturing.
2. It is the main communication protocol used in automation for (initially) semiconductor/electronics industries, however, today it has been widely adopted in photovoltaic and SMT industries too.
3. It provides a communication interface between equipments and host systems.
4. Unlike other communication protocol like PLC, it enable equipments from variety of vendors to communicate using standard and consistent protocol with various type of Host systems. 

 To understand the SECS/GEM standards you will need to purchase the following 3 basic standards from SEMI:  

1. SEMI E30 GEM Standard - This is the "Brain" that defines the behaviours of equipment (Business Rules), state machine and some rules like which SECS-II messages should be used, in what situations, and what the resulting activity should be. It also defines the functionalities like Status Data Collections, Trace Data Collection, Alarms Management, Spooling, Remote Command, etc.
2. SEMI E5 SECS-II - Defines the details of the interpretation of messages (APIs) exchanged between equipment a host. It also defines message inputs/outputs data structure, data item format, acknowledgement codes, etc.
3. SEMI E37 HSMS - High Speed SECS Message Services. This is a transport layer based on TCP/IP protocol and a successor of the previous SEMI E4 SECS-I standard that is based on serial communication. This is also the layer where the SECS-II messages are encoded into HSMS message format.

SECS/GEM Data Items

SECS/GEM is an industry standard, that defines standard process of communication between equipment and fab host software for controlling and monitoring purposes. By connecting SECS/GEM equipment, fabs can immediately gain operational benefits. Factory hosts can collect data in multiple ways. Along with event reports, the fab host often requires to poll the equipment for current data values. The host can directly request Data values , or can be sampled periodically in a trace report this process is called Data Polling

There are 3 categories of Data Items defined in SECS/GEM standards:

 

Status Variables (SV)

Status variables are data items that identify the status of the equipment, or any of its components, such as sensors, meters, etc. Examples of status variables for process equipment are – Temperature, Pressure, Gas Flows, RF Forward Power, Spin Speed, etc. These data items are generally not attached to events such as lot start, wafer start, etc. A factory host can query the status variables to the equipment any time or can define trace data setup through which it asks the equipment of supplying status variables at regular intervals. A factory host cannot change status variables of the equipment.

Data Value Variables (DV)

Data value variables are data items that are related to a certain event, such as lot start, alarm/error occurring on the equipment, wafer processing/measurement complete, etc. Examples of data value variables are – LotID, SlotNumber, CurrentRecipe, etc. These variables change only when a certain event occurs, such as selecting a recipe, starting lot processing, etc. A factory host queries Data Value variables through defining reports and associating the reports to events.

Unlike status variables, data value variables may not have a value. For example, one of the data value variable is AlarmID, which designates the ID of the most recent alarm. However, it can be empty if there haven’t been any alarms since the equipment was turned ON. A factory host cannot change the data variables of the equipment.

Equipment Constants (EC)

Equipment constants are data items related to the configuration of the equipment – they could contain items related to the equipment hardware, software or SECS/GEM software. Unlike status variables and data value variables, a factory host can change equipment constants through SECS messages. Examples of equipment constants are – PumpDown Time Limit, Equipment Standby Time, Pins Up Wait, etc.

Data Properties:

The Data types listed above have similar properties so that it’s convenient to define the data. The equipment supplier is required to provide these properties in a SECS/GEM manual so that the fab host will be able to understand and communicate with the data. Below are some of the important data properties of the Data Types:

• ID – It’s a numeric ID that must be unique in the SECS/GEM interface. These IDs can be grouped by data type and are referred to as SVIDs (Status Variable IDs), DVIDs (Data Variable IDs) and ECIDs (Collection Event IDs).
• Name – It’s a name assigned to a data item so that we can identify it easily.
• Format –Data type of the item.
• Data formats can be simple (numeric, ASCII, Boolean) or complex (arrays, lists, structures). For example, numeric types can be I1, I2, I4, I8 (signed integer types of different byte length), U1, U2, U4, U8 (unsigned integer types) and F4 or F8 (floating point types).
• Array types and List contain multiple values in the data item. For example, image data will be formatted as a Byte Array.
• Structure types contain a specific type of data. For example, a variable may represent a slot map which contains carrier information and also list of slots with their wafer placement status.
• Value –It’s the actual value of the data item. Data values are in an accurate, efficient, self-describing binary format so that its easy for the host to interpret the data. The data format allows collection of more data and with more efficiency.

Alarms & Collection Events (CE) also have IDs and names for their identification.

Data Polling :

The fab host often gets data on a regular intervals through event reports & trace reports and that it defines. SECS/GEM also provides a system for the fab host to poll data based on its needs.

Fab Automation services.

AUTOMATION BENEFITS in SEMI CONDUCTOR INDUSTRY AND EINNOSYS SOLUTIONS TO IT

Automation in factory is an important decision to be taken at management level.
The level of automation at any fab depends on several factors, but primarily the volume in wafer starts or outs, age of equipment, complexity of process, etc. The other main aspect to fab automation lies with the kind of experience and technological maturity of the manufacturer. Setups with longer exposure to IC manufacturing and skilled manpower are more prepared and adaptable to integrate automation solutions within their fabs and various production sites. This may include systems for Automated Material Handling, Planning , Simulation, Manufacturing Execution Systems, which include production dispatching and scheduling system and also Advanced Process Control systems and so on.

Basic automation includes preventing wrong recipe errors by the technicians by automating recipe selection through GEM/SECS. Advanced fabs have far more automation done which includes Fault Detection and Classification (FDC), Yield Management software, Recipe Management System, Automated Material Handling System (AMHS), to name a few.
Semiconductor manufacturing is undoubtedly the most complex manufacturing environments. Reasons for this being strict production processes, reentrant process flows, complex expensive equipments, variable demand, high levels of automation and an huge pull of data. Yet, despite having various challenges, semiconductor manufacturing is a key industry in many industrialized nations and contributes substantially, both directly and to the global economy. With the entry of highly automated wafer fabrication facilities (fabs), there is a industry trend to extend the traditional automation scope to integrate with advanced technologies.
Semiconductor technology grows very fast and thus there is a strong positive force to increase productivity using the existing assests . And this positive force has lead to the need of full automation to increase the existing productive. In fab automation, technological upgrades have to be taken into considerations on continuous bases.
We provide factory automation solutions, systems integration and consulting services to wafer fabs, assembly and test facilities across the globe.
We offer various products for FABS and ASSEMBLY facilities.
Our Fab Automation solutions include:
Yield management software
Cycle time Improvement
Improving OEE/Throughput
Advanced Process Control (APC)
Fault Detection & Classification (FDC)
Saving Manufacturing Cost

SECS GEM Improvement

Einnosys offers various solutions for Yield Improvement, ranging from simple barcode scanning of the lot boxes to very complex analysis of yield related issues by correlating end-to-end wafer data. Our team members have decades of experience in improving yield at all areas of Assembly, Test, Packaging factories and FABs. In addition to implementing complex yield improvement projects, our staff has published technical papers on how to use innovative, out-of-the-box automation to improve yield in factories.

 

Yield Management Solutions:-

1. Host applications or station controllers that download and/or select recipes upon barcode or RFID scanning of lot boxes and remotely starting process.
2. Collection and analysis of alarms, events and other critical process parameters from equipment through SECS/GEM or other means and correlating with other data such as that from MES or from other equipment 
3. For Wafer FABs, correlating end-to-end wafer data: From epitaxial -> inline process <-> inline metrology<-> electrical testing <->Final Test
   
    
4. Use feedback and feed-forward approach to feed metrology data to process equipment to improve yield 
5. More Detail...

SEMI PV2 (Photovoltaic Manufacturing)

The EIS TF(European Equipment Interface Specification Task Force ) decided to incorporate the already existing SEC/GEM standards in the Semiconductor Industry as the base for host communication through PV industry. This is the time when SEMI PV2 standard came into existence.

 

SEMI PV2 is the standard that defines a common equipment communication interface for PV (Photovoltaic Manufacturing) production system and gives various benefits to the PV industry.

This standard was developed by European Equipment Interface Specification Task Force (EIS TF) to minimize the efforts put in by the equipment suppliers to develop and maintain various equipment communication interfaces and to create a strong base for deploying advance factory management and to control software systems.

Equipment integration was a very costly and time consuming affair before this standard was implemented in equipment production industry.

With the implementation of this Standard both the manufacturers and the suppliers will be benefited in the following ways:

• Manufacturers need not specify ,test and integrate specific interfaces to ensure IT functionality at the factory level

• Suppliers need not implement and maintain customer specific interface

• Shorter break down time as there would standard IT integration process

• As the processes are standardize, thus will lead to yield improvement

• Simplified requirement specification and testing as the testing can designed in a generic way for all the interfaces

• This will lead to increased potential cost saving as the manufacturers’ are in better position to analysis integration risk and efforts.

This standard outlines one of the best practices which will help in great value addition to the semiconductor and PV industry.