Reduction of Laser Running Cost (Cost of Operation)
4. Reduction of the Cost of Downtime (CoD)
4-1. Actual Figures in CoD Reduction and Future CoD Reduction Plan
Figure 1 shows the reduction in CoD achieved after the fourth quarter of 2006 and the reduction plan through 2009. It shows total downtime caused by the laser in every quarter since the fourth quarter of 2006. (However, the figures on and after the second quarter of 2007 are forecasted ones.)
Figure 1: CoD Reduction and Future CoD Reduction Plan
4-1-1. Shifting unscheduled offline downtime to scheduled offline downtime
In the fourth quarter of 2006, 36 hours of downtime were generated; most of the time was unscheduled offline downtime. This unscheduled offline downtime was caused by initial defects that occurred when the GT-60 series started being used for mass-production. In order to reduce this downtime, we took aggressive measures to fix the defects in the field to achieve a dramatic reduction in the unscheduled offline downtime in the first quarter of 2007. On the other hand, the scheduled offline downtime required for repair in the field has been increased. However, occurrence of an accidental error causes serious downtime of the laser. Therefore, it can be considered that the productivity of the laser has been greatly improved by taking this measure.
4-1-2. Reducing gas refill time, step 1
In the first quarter of 2008, we took a measure for reducing the downtime caused by gas refill. We introduced new software and achieved extension of the gas life to twice as long as the conventional one, thus reducing the downtime to half of the conventional downtime.
4-1-3. TGM
We plan to introduce the Total Gas Manager (TGM) from the third quarter of 2008 to further reduce the scheduled online downtime. This enables the number of gas refills per year to be reduced to 24, while gas refill is determined by not the number of pulses but the number of days. This will allow a great reduction in downtime.
Figure 2 shows the TGM concept. TGM introduces new hardware/software to minimize an error caused at injection/exhaust of the laser gas, thus extending the gas refill interval.
Figure 2: TGM Concept
Figure 3 shows the TGM performance evaluation result. Generation of a laser gas error causes the chamber gas pressure to rapidly rise and reach at the upper limit. This evaluation proved that introduction of TGM caused the laser performance to be stable in the entire gas life of 15 days for 2500 Mpls without any pressure rise observed. At the same time, the measured laser performance items were checked. As a result, it was confirmed that all the performance items met the laser specifications.
Figure 3: TGM Performance Evaluation Result
4-1-4. Other downtime reduction measures
We at Gigaphoton take proper measures such as further expansion of repair activities in the field, reduction in module replacement time, preventive maintenance, and self-diagnostic functions of the laser, to further reduce the downtime. In 2009, we are aiming at reduction of the downtime to 1/7 of the downtime in the fourth quarter of 2006.
