The value of a single leading-edge semiconductor wafer is estimated at $17,000*. Downtime on one process tool alone can interrupt production and rapidly cause setbacks in wafer output, yield and cycle time. Maximum process tool uptime is critical to profitability.
With limited insight into the performance of the vacuum and abatement system, and its impact on process tool availability, this Fab had to operate under a time-based maintenance approach.
Determined only by the age and run time of SubFab equipment, time-based maintenance couldn’t completely eliminate the risk of a down event. Large inventory of spare parts had to be readily available, putting additional pressure on supply chains. Also, unexpected demands were made on maintenance teams to provide additional service support.
In an event where the vacuum and abatement system shuts down unexpectantly, the cleaning, recovery, re-qualification of the process tool was estimated to be at least 500 hours of tool time each year. This figure was calculated across 75 process tools; each requiring 6-7 hours of additional maintenance per unexpected stop.
Time based maintenance wasn’t enough, if the Fab wanted to meet growth and performance targets. Unexpected downtime needed to be avoided at all costs but without enough insight to quickly identify root causes of system issues, increased routine maintenance was the only option.
The Fab was challenged to deploy the right technical expertise in the SubFab, and as a result frustration between the Cleanroom and SubFab teams grew, leading to inconsistent communication and a lack of data sharing.
6-7 hours of additional maintenance per down event: Corrective Maintenance = 18 Hours vs Planned Maintenance = 11.5 Hours
In search of a more effective and accurate method to eliminate the risk of down events, this facility enlisted our help.
*Source: Centre for Security and Technology (CSET) REPORT, 2020
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