Automation leads to smooth operation

Published: 12-Mar-2003

Tool maintenance and tracking play an important role in any manufacturing process to ensure operations are not disrupted, but at Samsung it is "mission-critical"


While Samsung Electronics' wafer fab facility in Austin, Texas, US, is a highly complex manufacturing operation, Allison Keegan, who serves as master system administrator at the plant that produces 8in wafers for various electronic applications, has a very simple way to describe it.

"I've always likened this factory to a money tap," he said. "If you stop the flow of chips, you stop the flow of money, and there's no way to catch up because you're already running the operation as fast as you can. If you lose time in this fab because a tool is down, you're losing wafers, and any amount of wafer loss takes a lot of money away from the plant's bottom line." Clearly, tool or machine downtime is an anathema in any manufacturing operation, but as Keegan emphasises, the financial ramifications in a wafer manufacturing operation are especially severe. What is more, if the Samsung facility experiences downtime on even one tool that every wafer in the operation has to go through, it has effectively, in Keegan's words, "turned off the money tap". The need to ensure proper tool operation and maintenance is critical at Samsung, which employs several hundred sophisticated tools in its operation. One example of this technological sophistication is in the area of photolithography, where employees actually shoot a picture on the wafer, put the circuit board on the wafer at a microscopic level, etch the wafers, then go in and microscopically connect the circuits. Technology like this does not come cheap. In fact, with each of these tools representing a multimillion-dollar investment, Samsung's total capital expenditure in tools approaches €1 billion. Few companies can afford this kind of investment, but Samsung, a global company in semiconductor, telecommunication and digital convergence technology is one of the few. It employs around 64,000 people in 89 offices in 47 countries and is the world's largest producer of memory chips, Smart Card Chips, Display Driver ICs, TFT-LCDs, CDMA mobile phones, monitors and VCRs.

Financial incentives The need to protect its financial investment in these tools goes hand-in-hand with the need to keep quality product flowing out of the company – meeting both requirements is what keeps the "money tap" open. Consequently, Samsung turned to Brooks–PRI Automation Inc, based in Chelmsford, MA, US. The company, which delivers total automation for semiconductor manufacturing, helped Samsung install and implement its Xsite computerised maintenance management system (CMMS). CMMS is an integrated software package that provides a means of controlling all aspects of equipment maintenance activity – specifically for semiconductor manufacturers – from breakdown analysis and work order control to condition monitoring and preventive maintenance scheduling. Xsite is based on an open, object-oriented architecture that gives users the ability to choose from a number of different factory applications and databases. "We were looking for a very strong preventive maintenance (PM) manager," Keegan said. "Based on Brooks-PRI's demonstration of the product and our specifications, we were convinced that Xsite was the perfect tool for managing the PM function and that it could also play a key role in our overall equipment maintenance." According to Keegan, Xsite has provided numerous benefits, not least of which has been creating an almost paperless operation. "The biggest benefit is that we've been able to automate our preventive maintenance, which had previously been a manual operation," said Keegan. "Before implementing Xsite, we were relying largely on a huge volume of paperwork, including Excel spreadsheets. Xsite has allowed us to perform PMs on a weekly, monthly, quarterly and semi-annual basis, while also linking them together and attaching customised checklists to them. "In addition, the paperless aspect allows us to maintain extensive equipment documentation on-line, which not only makes it easier to access than paper, but also eliminates repeated departures and re-entry into our production area. The time savings in tool maintenance and repair is tremendous." Xsite also provides a PM trigger that allows an operator to automatically idle a piece of equipment when critical PM checks still need to be performed. The result is that production waste is reduced, and machine consistency and yield are optimised. One of the problems Xsite alleviated for Samsung was instances of PM checks being skipped and tools going down because the PM checks weren't always performed in a timely manner. Some of these PM checks must be performed on an hourly basis; if they are not, the financial ramifications can be dramatic. By employing Xsite, employees no longer have to lean on unreliable and largely ineffective methods – emails, postings, etc – to be reminded of PMs. "We've significantly decreased the human error factor in our PM checks," Keegan said. One of the primary factors leading to Samsung's choice of Xsite was its ability to interface to the manufacturing execution system (MES) that physically controls the movement of the wafers through the production facility. The MES system is FACTORYworks, another Brooks-PRI product, which provides an interface with Xsite. When FACTORYworks tracked the state of the tools in the fab, Samsung wanted to ensure that the information was communicated to Xsite as the CMMS reflects the tool status (up, down, PM) controlled by the FACTORYworks MES system.

State modelling "Another strong point of Xsite," said Keegan, "is the product's SEMI E10-compliant state modelling capabilities, which help track variables such as scheduled time, unscheduled time and productive time. Samsung designed a sophisticated state model that displays all the different states of a tool – almost 30 states in all. It is now possible for Samsung to determine, among other things, if a tool is waiting, if it is down and waiting on parts, or if it is down but waiting on resources or a specific vendor to fix it." Ultimately, Keegan says, at Samsung we can now "slice and dice our maintenance information any way we want to do it". Xsite provides a comprehensive set of reports, which Samsung has augmented with a number of custom reports, allowing the company to track overall tool performance and PM metrics more closely and accurately than ever before.

Impressive results "You can't put a price on the automated reporting and analysis that we've been able to produce. Before, you would know how long a machine would be down but you wouldn't know why," Keegan explained. "And even if you could figure out why, the information to verify your diagnosis wouldn't be available until it appeared on a spreadsheet four months down the road. "With the reports we get from Xsite, we can be more proactive in determining and analysing trends, and do it in a very abbreviated timeframe." Using the real-time status board, Samsung employees can bring up a specific division such as photo, diffusion or CVD and display the status of all the tools located there. Furthermore, employees can colour-code the tools to indicate whether they are up or down, or running products. Keegan says that some employees etch their monitors with pictures of their tools because Xsite never leaves their screen. When a tool goes down, they see it 15 seconds later and they're on the phone finding a repair solution. "Having viable data available to us on a consistent basis has made a huge improvement in our PM programme," said Keegan. "We only have a few projects that we consider to be mission-critical in our facility; our PM programme is one of them, and Xsite is the centrepiece. It's one more item in our toolkit that helps operations flow smoothly, keeping us competitive in an ultra-competitive industry."

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