Semiconductor manufacturing involves hundreds of steps. These take place on a variety of tools: saws, furnaces, photolithographic steppers, testers, and other specialized equipment. Some of this gear requires little electricity, an example being a track transfer system that moves wafers from one spot to another.
Other tools demand substantial electrical power, and those needs are growing as process technology evolves. For instance, the next generation of steppers currently being rolled out use EUV, or extreme ultraviolet, lithography. They may require 10 times the power of the previous technology, in part because of a conversion efficiency of only a few percent of an infrared pump laser into the desired extreme ultraviolet output.
So, there is no one-size-fits-all solution that will work to ensure power availability and quality. Instead, what’s needed is a fit-for-purpose approach. That is, the power solution should be customized as needed for a specific task.
Let’s look at three examples:
- A cleanroom process system
- Wafer inspection systems
- Chemical supply, control systems and valves
The power solutions for all three of these systems differ. Consider, for instance, a common factor: an uninterruptible power supply (UPS). A UPS ensures that a temporary loss of power and transient power glitches don’t cause systems to fail or otherwise not function properly. That improves manufacturing efficiency, reduces scrap and increases product quality.
But, uninterruptible power supplies vary in terms of capacity and how they react to a power failure or glitch. Capacity must be greater for systems that consume more power or if the UPS is intended to run the system for an extended period. As for a power glitch, an example of that is a voltage sag, which can happen to a circuit when a heavy load switches on.
Applying fit-for-purpose principals to the three different systems results in sizing the UPS appropriately for the applications. The chemical supply control setup, for example, might need a single- and three-phase solution, with a 1-200 kVA UPS. In contrast, air handling might have a three-phase UPS with a capacity as much as 500 kVA and a wafer inspection system would be backed up by a UPS capable of supplying the power needed for the specific tool.
Of course, implementing a fit-for-purpose approach can also lead to a centralized UPS solution. As in the cases mentioned above, it will need to be appropriately sized and configured. The centralized solution can be more cost effective than the decentralized approach due to the efficiencies realized by aggregating the power needs of all protected equipment together. The choice of a decentralized or centralized solution will depend upon the situation.
Regarding this, the trade association SEMI (Semiconductor Equipment and Materials International) recognized the need for the better power quality when it approved SEMI F47, a standard for semiconductor tools voltage sag immunity. The standard specifies acceptable equipment performance in the event of a temporary voltage sag. The idea is to prevent problems, such as wafers being yanked out of a hot furnace and warping to the point of being scrap as a result or an ion implanter going out of calibration and needing time-consuming maintenance
The standard, however, does not cover utilities, like ventilation or exhaust fans, or other infrastructure, like network connections or fire and security systems. Failure of such systems can cause problems. An exhaust failure, for example, can make a production facility hazardous to workers as toxic fumes build up on the plant floor.
In addition to a UPS, another common part of customized power solutions are remote monitoring and system management. This capability allows collection of power data, and this information can then be analyzed to spot dangerous power trends and, therefore, problems before they develop.
Such fit-for-purpose solutions can include a complete electrical system. Together with power monitoring and a resilient architecture, this can improve sub-function operation, enable optimum use of energy, and, in our experience, save up to 30 percent on operating energy costs. Such a solution saves money in another way as well because it sizes the equipment appropriately, thereby eliminating the waste of, for example, too large a capacity UPS.
A customized solution will need to be carefully designed. For instance, the monitoring scheme, such as the frequency and type of data collected, will vary by application. Again, there is not a single approach that works best in all situations. Therefore, the best approach is for facilities and manufacturing teams to work closely, and ideally partner, with a knowledgeable power solutions vendor.
Finding and implementing the right power solution can save energy, protect your equipment and people and reduce waste in multiple ways. For semiconductor manufacturing, which must continually cut costs, that flexibility is important, as is the potential for critical cost savings. To learn more about specific critical power solutions that can optimize operations, click here.
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