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Training Training - Top of Page CVD - Temperature Variations After installing ModelWare® on a CVD tool, real-time information indicated that temperature variation always occurred in the first step of every wafer. Using ModelWare®'s real-time display capability, the tool engineer was able to determine the temperature variations. In addition he was also able to demonstrate the variations to other fab personnel. Increase Operational Efficiency - Top of Page Ion implant - Vacuum Pressure Spike Within minutes of connecting ModelWare® to an ion implant tool and looking in real-time at the tool operation, the tool engineer noticed a sharp spike in the vacuum pressure each time an ion implant event began. After seeing three consecutive spike occurrences on the trend plots, the tool engineer stopped production on the tool and pulled the chamber. Within a few minutes of searching for the problem, the tool engineer found a broken O-ring and quickly replaced it. The broken O-ring could have caused undue wear and tear on some of the more sensitive and expensive components in the tool, which ultimately would lead to scrap events. Etch - Metal Seepage Using ModelWare®, the tool engineer was able to detect how traces of metal from step 1 were seeping into Step 2 during the 7 Step process of a particular etch machine. The engineer viewed archived data with ModelWare® and generated off-line reports clearly showed the fault. He then initiated corrective measures. CVD - Exhaust Fluctuations A particular CVD tool is extremely sensitive to any type of exhaust fluctuations. The smallest exhaust fluctuations above or below the set limits will trigger the deposition sequence to automatically disable itself, causing wafers to receive partial deposition. These wafers cannot be fixed and are therefore scrapped. After installing ModelWare® software on the tool, the software predicted the exhaust spikes above and below the set limits many times. The tool engineer could then, with confidence, enable ModelWare® to send halt messages to the tool before the fluctuations caused scrap to occur. Investigating further with ModelWare®, the tool engineer was able to predict the exhaust error and correlate the problem to worn out or faulty valves. Etch - RF Spike At a production fab, ModelWare® was installed on an etch tool, and it "informed" a tool engineer that one wafer out of twenty lots had an RF spike affecting etch rate and end point. Studying real-time trend plots and off-line archived information, the tool engineer was able to see events that would likely lead to a tune position shift before the shift could cause major damage. The tool engineer reported the problem to the tool manufacturer, who in turn is forming a task force to correct the problem. Etch - Manometer Pressure Since installation, ModelWare® has been used for tool troubleshooting on a number of etch tools in a production fab. Normally, at this fab, an etch tool will be set to allow 10% tolerance on the manometer pressure sensor before the tool will alarm out. Using ModelWare® to collect data that shows sensor spikes such as "bursts" in manometer pressure, the tool engineers could proactively take corrective actions to avoid scrapped wafer events. Increase Availability Efficiency - Top of Page Etch - Electronic Chuck After installing ModelWare® on an etch tool and performing a regular tool "check-up", the tool engineer started to switch between display screens to view the data that the software was collecting. The tool engineer wanted to verify that a recently installed electronic chuck that correlated two sensors was operating correctly. Suspecting that there was a problem, he then used ModelWare® to view archived multi-sensor plots to confirm the discrepancy between the sensors and made the necessary adjustments to the tool. Etch - RF Power During the initial evaluation of ModelWare®, the tool engineer noticed unusual behavior with the RF power. Watching operations in real-time he noticed that, when the RF-fwd power was turned on, there was a large spike on the trend plot. Etch - Irregular End Point Trace Data Every once in a while, the recorded end point trace data was irregular. However, there was no difference in wafer quality. The tool engineer working on the tool had no idea why this was happening. After ModelWare® was installed, it was determined that RF oscillations caused the end point trace data to have different shapes. A tool service person was called to check out the problem, the necessary adjustments were made to the tool and the oscillations disappeared, and so did the end point trace data irregularities. CVD - Incorrect Tool Adjustments By viewing archived trend plot data from a CVD tool, the tool engineer was able to see that some profiles were adjusted incorrectly. Using Triant's ModelWare®'s realtime viewing capability, the tool engineer also found an MFC that was drifting outside of its allowable limit. Qualify Efficiency - Top of Page CVD - Belt Speed/Gas Flow Adjustments On a CVD system, two critical operation parameters determining the quality of the deposition are belt speed and gas flow. An injector change is performed every 10-40 production hours, and the belt speed and gas flow must then be re-adjusted by the operator. Sometimes the belt speed or gas flow adjustments are incorrectly adjusted. Using ModelWare®'s "tool halting" feature, one fab was able to save over five full lot scrap events over a period of several months. Etch - Mode Shift On an etch tool, a problem occurred where the plasma exhibited a "Mode Shift". The plasma was dispersed instead of concentrated in the chamber, causing the wafer to be under-etched. However, the tool engineer set up a model with ModelWare® to detect this problem as soon as it occurred. The detection of this fault saved the wafers from being re-worked. Without ModelWare® this problem would have been hard to detect because it has no effect on the normal recipe input parameters. Etch - Etchant Tank Temperature Using ModelWare®'s realtime display capability, the tool engineer could see that the etchant tank temperature control system was not functioning properly. Normally, the temperature should be within a certain bandwidth. The temperature was outside the limit at various times during the run. By viewing the archived trend plot data, the tool engineer was able to determine how long the temperature had been outside the allowable limits. This information is crucial for him because the longer the time it takes the temperature to stabilize and reach the set-point limits, the longer it takes to reach normal processing. Etch - Fault Identification An event occurred where several lots were scrapped. The production people thought one of the etch tools was at fault. The tool engineer working on the etch tool in question used ModelWare®'s archive data viewer to investigate the question. Within two hours he was able to show his management that the tool had not caused the scrap event. In contrast, there had been an earlier large scrap event, and again management thought that it had been caused by the etch tool. However, because ModelWare® was not installed on this particular tool, the tool engineer could not show that the tool was not to blame. Etch - Helium Clamp Flow Using ModelWare®, a tool engineer was able to easily see a recurring helium clamp flow problem. He viewed the archived trend plots and was able to see that the actual helium clamp flow for a number of the wafers in the lot had risen and that the problem gradually worsening as the clamp flow increased.
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