Increasing Energy Efficiency


Click to EnlargePete Singer

Being "green" is a great idea, especially if it saves money. The semiconductor industry is in a somewhat unique position in that there are plenty of opportunities to reduce energy and thereby cut costs in the manufacturing operation. And, as the world wakes up to how much energy is being consumed by data servers and other types of electronics, the demand for a whole new wave of chips that consume less power provides opportunities for growth.

In this issue, we present three features dedicated to this topic. First, as noted on the cover, many fab engineers can find a good starting point literally beneath their own feet, in the subfab. Through the use of a central control system, equipment in the subfab such as vacuum pumps and process exhaust abatement systems can be optimized so that it's only "on" when needed. The result is a 20% reduction in energy consumption, without impacting environmental, safety or health issues.

The authors report that in addition to saving energy, syncing up the subfab with process tools also offers significant savings in installation cost and floor space, by reducing the number of connections of forelines, exhaust, water and power lines, communication cables and racking by more than 50%.

Another feature reports on energy saving initiatives at Texas Instruments. Last year, the company was able to realize cost savings by slightly relaxing some specifications for humidity, air recirculation and wafer fab pressure, for example, and by using heat recovery from exhaust systems. TI also installed a "green" living roof on a portion of a new assembly/test facility in the Philippines.

That's only the beginning, though. In 2010 and beyond, author Sunil Thekkepat says TI will be concentrating on three areas that will further enable effective energy savings: infrastructure retrofits, equipment upgrades and manufacturing variability. The first two initiatives have a lot to do with the age of existing fabs and equipment (some almost 50 years old). Thekkepat notes that companies have little economic imperative to replace older working equipment with new, energy efficient equipment. "Equipment manufacturers need to work with semiconductor manufacturers to make it economically viable for fabs to remove functional, yet inefficient equipment, from service and replace it with new, more efficient equipment," he says. I'm not sure how that would work, but it's an interesting call to action.

Another call to action is to power down equipment when it's not in use. Thekkepat says that manufacturing operations stay on, even when they are not processing wafers. "To make energy consumptoni more variable, tools and support equipment have to come to a reduced energy state similar to "start stop" engines commonly found in today's hybrid vehicles," he writes.

To that end, TI has been working with SEMATECH on "idle mode" studies. A few areas have been identified for reduced energy use – RF generators, vacuum pumps, point of use chillers, and abatement equipment – but the industry needs to work together to identify other areas (call to action #2).

A third feature in this issue addresses the important role that semiconductors play in the world at large when it comes to energy efficiency, particularly power management ICs. The use of these ICs range from larger electronic system such as a cell phones, TVs and computers, to applications enabling new power saving technologies, including smart meters and grids and more efficient lighting solutions.

The authors describe the technical challenges of power management ICs when it comes to silicon, metallization and packaging, and go on to identify future challenges, including micro-energy harvesting for hand-held applications. Simple examples of micro-harvesting are wrist watches that achieve power from the kinetic energy (vibration) supplied by the wearer or from solar energy. Sources for energy harvesting can include energy from vibration, temperature differentials, light and RF waves.

The presents yet another call to action: develop hybrid solutions that combine traditional energy sources with harvested energy, while also developing innovations in terms of energy storage (i.e., thin film batteries), power conversion and power management at the chip level.

The semiconductor industry has many opportunities to increase energy efficiency: by reducing energy consumption in manufacturing operations, introducing new technologies and chips that are more energy efficient, getting involved in smart meters and other energy-saving applications, and using semiconductor technologies to harvest and store energy at the micro level.

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