For many years the semiconductor industry’s wafer fabrication facilities, where semiconductor devices are manufactured on [principally] silicon substrates, have universally embraced and mandated the GEM standard on nearly 100% of the production equipment. This includes the complete spectrum of front end of line (FEOL – device formation) and back end of line (BEOL – device interconnect) processes and supporting equipment. Most equipment also implement an additional set of SEMI standards, often called the “GEM 300” communication standards because their creation and adoption coincided with the first 300mm wafer manufacturing. Interestingly, there are no features in these standards specific to a particular wafer size.
Together, the GEM and GEM 300 standards have enabled the industry to process substrates in fully automated factories like Micron demonstrates in this video and GLOBALFOUNDRIES demonstrates in this video.
Specifically, the GEM 300 standards are used to manage the following crucial steps in the overall fabrication process:
Additionally, the GEM standard enables
After wafer processing is completed, the wafers are shipped to a semiconductor back end manufacturing facility for packaging, assembly, and test. Historically this industry segment has used GEM and GEM 300 sporadically but not universally. This is now changing.
In North America, SEMI created a new task force called “Advanced Back end Factory Integration” (ABFI) to organize and facilitate this industry segment’s implementation of more robust automation capabilities. To this end, the task force is charged with defining GEM and GEM 300 support in back end equipment, including processes such as bumping, wafer test, singulation, die attach, wire bonding, packaging, marking, final test and final assembly. As its first priority, the task force has focused on updating the SEMI E142 standard (Substrate Mapping) to enhance wafer maps to report additional data necessary for single device traceability. Soon the task force will shift its focus to define GEM and GEM 300 back end use cases and adoption more clearly.
GEM was selected for several reasons.
The ABFI task force has already proposed some changes to the SEMI E116 standard (Specification for Equipment Performance Tracking, or EPT). EPT is one of several standards that can be implemented on a GEM interface to provide additional standardized performance monitoring behavior beyond the GEM message set. This standard already enables reporting when equipment and modules within the equipment are IDLE, BUSY and BLOCKED. A module might be a load port, robot, conveyor or process chamber. When BUSY, this standard requires reporting what the equipment or module is doing. When BLOCKED, this standard requires reporting why the equipment or module is BLOCKED.
After analyzing the requirements of the back end industry segment, the task force decided to adopt and enhance the EPT standard. For example, the current EPT standard does not make any distinction between scheduled and unscheduled downtime. However, a few minor changes to E116 would allow the factory to notify the equipment when downtime is scheduled by the factory, greatly enhancing the factory’s ability to track overall equipment effectiveness and respond accordingly.
Many of the GEM 300 standards can be applied to some of the back end equipment when applicable and beneficial. The task force is defining specific functional requirements and evaluation criteria to make these determinations and publish the resulting recommendations in a new standard. Representatives from several advanced back end factories are already closely involved in this work, but more participation is always welcome. For more information, click the button below!