Large semiconductor fabs can devour electricity at clip of 100 megawatts per hour -- enough to power 50,000 homes1 and, according to a McKinsey study, more than automobile plants and oil refineries consume. So ravenous is their electricity consumption that some fabs have resorted to building their own captive power plants. Oversize fabs, depending on their location and local rates, can run up utility bills as high as $25 million each year, with electricity accounting for up to 30 percent of operating costs.
Fabs use electricity to power HVAC, run cooling water, and for basic infrastructure. But the vast majority of electricity is gobbled up by semiconductor manufacturing process tools and their sub-fab support equipment such as vacuum pumps and abatement systems. In a typical fab, as much as 44 percent of the electricity is consumed by the processing equipment2. It’s not so hard to imagine. Etch and deposition tools need power to strike and sustain plasma, with multiple 1,000+ Watt RF power supply feeds per chamber and four, six or more chambers per tool, and vacuum pumps spinning and abatement running. The power load adds up quickly.
Watts and Watts
The good news is that process tools aren’t processing wafers all the time. The bad news is that, in the past, there was no good way for the fab to know when process tools and support equipment weren’t running processes. Turning equipment off, or reducing power when not processing, wasn’t coordinated and standby states weren’t defined for readiness for a seamless power-up and return to processing.
So what to do? Take action. That just what industry volunteers did when they met within SEMI’s Standards program and defined an equipment “idle mode” (SEMI E167 and SEMI S233). More recently, a SEMI Standard (SEMI E1754) was developed to define energy saving modes – how process tools communicate with sub-fab equipment, to reduce utility consumption when wafers are not being processed by the tool. Importantly, it also provides guidance on the standby state to return to full performance when the tool is needed to process wafers.5
Good to be Idle
The semiconductor industry is now increasingly adopting a “smart idle” approach using these SEMI Standards. Fabs implementing these standards to take advantage of process tool idle periods can save more than 4.3 million € annually, according to AIS Automation modeling.6 This study also points to a savings of more than 16,000 tons of CO2 per year, the equivalent of taking more than 10,000 cars off the road.
Who knew that recognizing when to be idle could bring such big rewards? If only I could apply that to my own life, but, for now, I will have to leave it to the fabs.
SEMI International Standards volunteers make a huge difference to our industry every day. If you want to join the over 5,000 SEMI Standards volunteers (or join SEMI’s Sustainable Manufacturing eForum), with representation from over 2,000 companies, it’s free! Don’t be idle for this one, click here to join! http://www.semi.org/en/standards/P041367
1Bringing Energy Efficiency to the Fab, McKinsey 2013
3SEMI E167-1213 - Specification for Equipment Energy Saving Mode Communications (EESM)
3SEMI S23-0813 - Guide for Conservation of Energy, Utilities and Materials Used by Semiconductor Manufacturing Equipment
4SEMI E175-1116 - Specification for Subsystem Energy Saving Mode Communication (SESMC)
6SEMI Standards a Potential Help for Saving Energy, Bert Mueller, AIS Automation 2016