Wanted: More Fab Tool Part Standards
Source from: https://semiengineering.com/wanted-more-fab-tool-part-standards/
More complex equipment and advanced processes require higher reliability from thousands of parts.
As chipmakers ramp up the next wave of processes and grapple with how to reduce defect levels, they are encountering problems from an unlikely source—components inside of the fab equipment.
Defects are unwanted deviations in chips, which impact yields and device performance. Typically, they are caused by an unforeseen glitch during the process flow. But a lesser-known problem involves defects introduced by critical components and sub-systems in the fab equipment itself.
Generally, equipment vendors build systems with good components. But sometimes problems are caused by tool parts and faulty components, which can introduce unwanted defects on a wafer. That impacts chip yields and costs, and it can lead to excursions or unforeseen events in the fab.
Fab tool component issues have been lingering for years, but now there is an urgency to address the problem. Foundries, as well as logic and memory makers, are ramping up more advanced and costly processes in the fab. With costs rising and tolerances shrinking, device makers can’t afford any major problems in the manufacturing flow, such as a glitch with the process or equipment.
If there is a glitch with a part in a system, it’s not a simple matter to locate faulty components and fix the problems. For example, the more sophisticated fab tools incorporate more than 50,000 parts from dozens of suppliers. Other systems have fewer parts. Most tools incorporate chambers, pumps, RF generators, seals and valves.
Nonetheless, the issues with the fab tool components are sometimes problematic. “Foundries have repeatedly had quality excursions due to supplier variability and control gaps,” said Glenn Colton, senior director and head of global capital equipment procurement at GlobalFoundries, in a presentation at the recent Semicon West trade show. “We regularly investigate these quality excursions and almost always find out that we could have mitigated the risk if we had known there was a component quality issue before we installed that component into a tool. These lead to the need for more robust quality assurance and industry standards around these components.”
The problem is that less than 1% of tool parts have quality assurance standards, according to Colton. “We really have little knowledge of the tolerance that those components are built in. When I give a component to the fab, how do I know it’s going to work 100% of the time, first time right, and we are not impairing the equipment team’s ability to achieve their targets,” he said. “We also lack robust traceability. If we do have an excursion, most of our end clients want to know where this happened, how it happened, and what we are going to do to prevent this from happening again. W