Design for Automation: Its Time Has Finally Come
Jack Ghiselli, GW Associates Inc., Sunnyvale, Calif. -- Semiconductor International, 11/1/2000
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That is about to change now as the stringent requirements of the transition to 300 mm wafers forces the architects of fabs as well as makers of the equipment that goes into them to accept the reality that true factory-wide automation is coming at last.
The impact on new fabs will be felt all the way down to the bricks and mortar, because the traditional bays full of like equipment - the etch bay, the deposition bay, etc. - will have to change to assure the continuous flow of wafers in process throughout the fab. To avoid the traffic jams that could defeat the purpose, equipment will have to be sorted in such a way that each pod full of wafers has an optimum route through the process. These routes must be predetermined and designed in even before the fab is built. Our entire concept of technology flow will change and we are already moving in that direction with 300 mm facilities now on the drawing boards. My guess is that the benefits of automation will become so "mission critical" that many will be adapted even for 200 mm facilities.
Both the blessing and the curse of the fixed robotics systems we are relying on to increase productivity is that they are programmed in the host computer with sensors that tell them when to pick up a pod of wafers from one process step and transport it to the next without delays. That removes some of the flexibility we have had in the past with human operators, but the improvement in productivity will be worth it.
With the increased use of sealed minienvironment pods, a move made even more essential with the introduction of a known contaminant like copper into the process, cleanroom concepts will change dramatically. More of the human operator's time will be moved from the cleanroom to the gray room, and systems are likely to incorporate two control panels, so that they can be accessed and operated from either side, somewhat like providing two steering wheels on a car.
How do we, as an industry, prepare for this paradigm shift in factory layout? By addressing the reality that communications among the 60 or so types of process equipment in the fab and the host computer is absolutely essential. Because there are so many types, the process and metrology equipment becomes the "critical path" in achieving the automated fab - not the automated material handling systems or manufacturing execution systems.
"Connectivity" becomes a mission-critical element of the system design. Until now, connectivity has been an end-of-the-line add-on to most process systems. The focus has been first on results on the wafer, and when those are achieved to customer requirements a software connectivity is added on, either provided by an outsource or developed by the in-house software department.
Over the next year or so, I believe you will see all the major IC manufacturers begin to write automation requirements into their equipment specifications. That means, to even be in the running, an equipment vendor will have to provide assurance that its system meets those automation specs along with all the other specs you have come to expect. Intel is already doing it and Infineon is now preparing to do it. My guess is that the others will not be far behind.
Where does total automation begin? I believe it must begin with connectivity designed into fab equipment, not added on later.
Fortunately, the SEMI organization anticipated the need and has the primary standards in place that can make it happen. Working with the industry's long experience with the SECS/GEM standards, SEMI's committees have attacked the problems of communications in the automated 300 mm fabs and their efforts are supported throughout the global semiconductor industry. While they have yet to vote on an industry-wide name for these new standards, they are often referred to as ConX300.
Whatever you call them, the industry needs to pay attention to them because connectivity is going to be the key to mechanization of the automated fab of the future.
