Page 40 - PEN eBook May 2023

SEMICONDUCTORS SEMICONDUCTORS

THE PRICE OF ENTRY EVERY DROP IS PRECIOUS “upstream” category of “Scope 3” emissions, as defined highly popular with customers. “Four out of four of
The baseline technical standards required for With dried-up lakes and rivers making worldwide by the widely used Greenhouse Gas Protocol. Factors the customers I spoke with today inquired about
the infrastructure in a semiconductor fab are news last summer, it has never been more obvious that like energy use for production or transportation on this capability, which significantly decreases overall
high to begin with. The slightest contamination responsible use of water is essential. To continue and the part of a supplier are part of the purchaser’s construction duration,” Sinclair said.
from dust can jeopardize product quality, so fabs even increase water-hungry semiconductor production, responsibility, even though they have no direct control
typically operate under the cleanest of “cleanroom” it will be equally essential to adopt a recycling mindset over those activities. The large-scale investment To facilitate the construction process for customers,
conditions (ISO Class 1). High purity standards must from when shovels hit the ground. required by a new fab therefore also calls for close GF has invested in off-site fabrication shops close to
also be applied to the lifeblood of a semiconductor review of supplier sustainability practices in addition to major construction sites and is continuing to grow the
fab: its water supply. As the millions of transistors, Dominik Roth, global business development manager their technical competence. network. With subassembly work conducted at the
resistors and capacitors in a chip’s integrated circuit of sustainability at GF Piping Systems, pointed out prefabrication site, GF can deliver “laterals,” or partial
are built up on the substrate of a silicon wafer, layer that “circulating water to reduce consumption is In this context, products that do not need to be assemblies that can be transported a shorter distance
by layer, rinsing is required at many points. This part paramount.” And for reasons of both economics and transported long distances to the construction site to the factory and quickly installed on-site. Existing
of the process is essential, as even trace amounts community relations, semiconductor manufacturers have great appeal. In addition to other sustainability GF prefabrication sites in the United States include
of impurities remaining could change the wafer’s are taking note. Reuse of wastewater for cooling benefits, such as lighter plastic materials and the Shawnee, Oklahoma; Irvine, California; and Dallas.
electrical properties. purposes is a common first step, but interest in the company’s ongoing progress on fronts like recycling
more complex process of reclaiming waste streams as and renewable electricity, GF Piping Systems’ BUILD FOR THE FUTURE
To succeed in removing contaminants without feedwater for UPW systems is increasing. worldwide network of prefabrication has thus become The major crises in human history differ in the details,
adding new ones, fabs must use ultrapure water but they all have one thing in common: They call for a
(UPW) for rinsing. UPW has been purified of all other At one time, it was common for semiconductor reappraisal of the way things have always been done.
molecules to the point that it very nearly approaches manufacturers to recycle only about 40% of their Semiconductors may be here to stay, but when, where
100% H O. Approximately 1,400–1,600 gallons of wastewater, forcing them to find less sustainable and how they are made will continue to evolve. Every
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municipal water are needed to create 1,000 gallons treatment and disposal strategies for large volumes element in the process, right down to the pipes moving
of UPW. The resulting product’s chemical properties of water contaminated with toxic solvents or heavy water though the factory, will come under increased
are so different from tap water (including its metals. But by the mid-2010s, TSMC was able to report scrutiny in years to come. But as a generational
resistivity of 18.2 MΩ) that it is not safe for humans process-water–recycling rates of over 85%. Similarly, investment in capacity takes place across the U.S.,
to consume. for 2021, Intel reported using 16 billion gallons of fresh, another rare chance presents itself as well—the
reclaimed or desalinated water for manufacturing—but chance to build a more sustainable future, right from
Given the effort and expense involved in buying or also reported returning 13 billion gallons to surrounding the ground up.
creating UPW (which requires an elaborate three- communities or the environment.
stage process to make), semiconductor fabs must
also ensure that their fluid transport systems Planning for on-site water recycling at the
meet equally high standards to avoid reintroducing construction stage can thus build sustainability into
unwanted substances. A single fab site may include a plant’s operations right from the beginning, and Experienced partners like GF Piping Systems can make
up to 40 km of piping for the transport of UPW, and here again, an experienced design partner can help. semiconductor fab construction more sustainable, with
options including localized prefabrication. (Source: GF Piping
the conditions under which that piping was made With expertise in both process automation and fluid Systems)
matter just as much as conditions in the fab itself. transport, “GF has been supporting the semiconductor
industry’s efforts to build the most sustainably
As noted by Ted Sinclair, global sales manager for managed fabrication factories for more than 30 years,”
microelectronics at GF Piping Systems, any source Sinclair said. “Thoughtful collaboration and system
of contamination is unacceptable “in a process modeling from early in the project, with a vertically
where the distance between each transistor is integrated single partner from system design through
measured in nanometers. Our components make product manufacturing—that can really elevate the
sure that nothing impure makes its way into the final result.”
manufacturing process on a molecular basis. The
reality is, it’s both the high-purity resin we use and MAKE IT WHERE YOU NEED IT
the purity of the pipe-extrusion environment, the Perhaps unsurprisingly, the overall energy demands
cleanroom in which we extrude the pipe, that deliver of semiconductor manufacturing are considerable.
the high-purity results our customers demand.” A typical fab might use as much power in a year as
50,000 homes. A “megafab” might draw power more on
The Sygef Plus fluoropolymer piping system the scale of an auto plant or oil refinery. To find ways
is manufactured by GF from carefully screened to limit emissions, creative thinking may be required,
materials under ISO Class 5 cleanroom conditions. and examining all aspects of the supply chain is a
Rigorous testing, special packaging measures and must.
highly reliable jointing technologies for assembly
also serve to ensure the high purity of final Typically, about 20% of the greenhouse gas emissions
installations. associated with a semiconductor fab belong to the

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