Net zero goals target energy, emissions, water, and factory efficiencies.
The chip industry is stepping up efforts to be seen as environmentally friendly, driven by growing pressure from customers and government regulations.
Some manufacturers have been addressing sustainability challenges for more than a decade, but they are becoming more aggressive in their efforts, while others are joining them. A review of sustainability reports across the semiconductor industry shows chipmakers, equipment companies, and materials manufacturers are establishing targets for greenhouse gas emissions, water usage, and waste. In the last few years, the heightened interest in climate change has spurred new collaborative efforts, such as SEMI’s Semiconductor Climate Consortium.
The continued expansion of IC production necessitates new fab construction, which translates into more energy and water consumption, as well as material waste. Manufacturers can focus on their own operations and energy purchases, but the more challenging areas include changing chemistry away from fluorinated gases with high global warming potential and coordinating changes throughout the supply chain.
In the U.S., NIST’s Sustainable Manufacturing Initiative (SMI) defines sustainable manufacturing as “manufacturing processes that minimize negative environmental impacts, conserve energy and natural resources, are safe for employees, communities and consumers, and are economically sound.” [1] The environmental area requires targeted investment in conversions to new technologies and conservation methods to address:
Sustainability assessments of chip manufacturing span from the sourcing of materials and equipment to the actual shipping of a product. Within their purview, factories can control their production’s impact on air, water, soil, in addition to how much energy they use. They also have some control of energy purchase options, with companies moving to cleaner energy sources where available. For their upstream supply chain, companies can place requirements on their suppliers, but tracking products through multiple levels of hierarchy — up to 20 deep in some cases – is a massive challenge.
Fig. 1: Inputs and outputs for evaluating sustainability. Source: A. Meixner/Semiconductor Engineering
Resource-intensive manufacturing
The Greenhouse Gas Protocol [2], which provides the most widely used GHG accounting standards, is broken up into three emission sources:
Factories can minimize their energy usage, and they can purchase energy from more sustainable sources, but the industry faces multiple challenges.
“The semiconductor industry is a very big consumer of energy. From the financial perspective, it’s 15% to 30% of the OpEx. Now, with the recent increase in energy prices in some markets like Europe, this becomes higher,” said Dallal Slimani, vice president of semiconductor at Schneider Electric. “There is another challenge that is facing this industry with new fabs coming online. The current estimate is about 90 between now and 2030. This means that the energy consumption of this industry will increase dramatically. And when we look at some research, by 2030 the fab industry could be consuming more than 200 terawatt hours of electricity. In 2022 for the carbon footprint, we are talking about approximately 40 million tons of CO2.”
“Clients are keen on operationalizing their sustainability targets and goals for 2025 and 2030. This involves integrating environmental, social, and governance (ESG) impacts into their day-to-day supply chain systems and processes,” said Deborah Dull, vice president of global supply chain sustainability leader at Genpact.
A survey of sustainability reports shows the level of commitment across the supply chain.
ASE Group’s 2021 report says the company is “committed to improving our eco-efficiency and protecting the environment by continuously enhancing resources recycling, and reducing greenhouse gas (GHG) emissions, waste generation, wastewater effluent, and chemical usage. ASEH strives to develop and promote an environmentally friendly manufacturing and service concept in all facets of its enterprise. From material procurement, design, manufacturing, product use and disposal, we conscientiously incorporate environmental impact factors at all stages of life cycle to provide green and low-carbon manufacturing services.” [3]
Brewer Science’s 2022 report echoed those concerns, “Environmental responsibility is an ongoing priority at Brewer Science, as we continue to reduce our carbon footprint and partner with our customers, suppliers, employees and the community to find new ways to have a positive impact on the environment,” wrote Matthew Beard, executive director of strategic planning, management systems, and sustainability. [4]
Meanwhile, UMC’s 2022 report documents its early environmental investment. “Since 2005, UMC has fully implemented life cycle assessment in all its fabs, which covers from “cradle to gate” (UMC shipment) and assesses items including energy, raw materials, and emissions,” the report says. “The results of the 2022 UMC Environmental Impact Assessment revealed that the environmental impact of “Climate Change” and “Respiratory Organics” is greater in the production stage than that in the raw material stage.” [5]
The list goes on. Every major player in the chip industry has published an environmental statement of direction.
Reducing GHG emissions and energy
Greenhouse gas (GHG) emissions, measured in terms of CO2 equivalent tons, is the metric most closely associated with climate change.
“Today, the impact of semiconductor manufacturing has been evaluated to be 100 megatons of CO2 equivalents per year. This represents scope one and two emissions only. It is just the activities of the foundries without the upstream, scope three,” said Cédric Rolin, program manager for sustainable semiconductor technologies and systems (SSTS) at imec.
Sustainability is a key issue of fabs owners but also packaging operations run by OSATs.
“We believe innovation and collaboration are important to support our customers’ sustainability goals. We continue to engage with our customers to better understand their sustainability priorities. Climate change mitigation is one of the most concerning areas for our customers,” said Hye Ju Lee, vice president of compliance for Amkor Technology. “Last year, we undertook initial steps to establish a new GHG emissions reduction goal by refining our GHG inventory process to include emissions produced throughout the value chain. As a first step, we completed a review of our GHG inventory and have developed a complete and robust GHG emissions inventory. We are continuing our work on this important initiative to set a new GHG emissions reduction target to respond to our customers’ expectations.”
Greenhouse gas emissions cover manufacturing recipe gases and the energy sources. And to fully address the industry’s impact the whole supply chain needs to be involved.
“Lowering greenhouse gas emissions is one of the semiconductor industry’s most complicated challenges due to the energy needed to make chips and the unique requirements of the manufacturing processes. This complexity is compounded as the semiconductor ecosystem must also expand globally to meet the growing demand for chips,” noted Chelsea Hughes, senior corporate communications manager for global impact at Intel. “Getting to net-zero requires identifying, developing and piloting novel green chemistry solutions, abatement tools, new equipment designs and facility systems, many of which do not exist today. As one of the world’s largest semiconductor companies doing research, design and manufacturing, Intel is deepening its long-standing collaboration across the ecosystem to achieve a future of more sustainable computing.”
To begin to decrease emissions related to energy consumption knowledge is power.
“For a fab, one of the first things that they need to do in order to decrease to decrease carbon emissions is to know the source electricity. Depending upon the company they can influence a shift in the way electricity is produced in the region or in the country. Or they can buy green electricity on the energy markets. But, of course, there’s only so much green electricity available out there,” said imec’s Rolin. “At the end of the day, it will only be possible to become greener if more renewable electricity is put on the energy markets. The more the industry pushes for a shift in the local energy policies the better. They are not totally in control, and this can be complicated, depending upon the geographical location.”
The ideal target is net-zero emissions from energy, but it takes a plan to get there. Industry 4.0 projects can help with measuring and reducing energy by providing data with much higher granularity and enabling automation.
“Clearly, we want to address the major energy consumption. But of course, everything starts with a measure and then benchmarking that measure with best in class. Then we move into more of a roadmap, trying to understand how to reduce bringing that to zero, of course, is impossible,” said Paolo Butti, vice president of global industry, OEM & emerging markets at Rockwell Automation. “We can do it with Scope 2 with a smart system that would automatically understand even when to stop, when to shut down. Restart energies do not process either on existing or new technology that can help like measure and optimize energy consumption.”
Energy experts also cite the usage of digital solutions to track and manage energy consumption.
“We have the digital platforms that will allow us to capture all the energy consumption data with context from different sources, said Schneider Electric’s Slimani. “This gives visibility and could be in one country or in the region. Depending on the needs of the customers, we leverage data analytics to bring additional context — for example, comparing the different steps where it’s relevant and identifying additional levers of energy efficiency.”
Those levers take various forms. They can include switching to LED lighting, upgrading HVAC systems, or energy-efficient design in new factory construction. Many companies follow the ISO 50001 Energy Management System standard to set targets, identify improvements and track progress. [6]
“The objective is to reduce our carbon footprint as a company, and every step we take within the company in terms of manufacturing and the products that we support,” said K.C. Shekar, senior director of strategic marketing at Winbond. “That includes reducing our electricity use by 90%, and carbon and emission reduction by 60%. We’ve passed the ISO 50001 energy management system certification and the RBA (risk-based assessment) factory inspection.”
Every bit counts, and managing a process tool’s energy was cited in a recent Lam Research announcement. [7] “Lam is focused on developing smarter, more efficient products and processes to measure and reduce the greenhouse gas emissions of its tools. New sustainability features in 2022 included the release of a new ECO Mode feature for its 2300 and Sense.i etch tools, which saves on peripheral energy in idle mode and results in faster tool time recovery.”
Reuse is becoming a hot topic as companies become more frugal in production.
“Energy efficiency and sustainability is an industry focus. To improve the footprint, we need to consider the entire product lifecycle. With our Smart Cut technology, we enable 10-15 times reusability of the same substrate,” said Christophe Maleville, CTO at Soitec. “We multiply the efficiency of every crystal that is produced. That’s a very important element of the footprint on the environment.”
AI-based process control can help eliminate processing on wafers that eventually will be scrapped.
“Semiconductor fab emissions come primarily from Scope 1 process gases and Scope 2 electricity consumption. Our AI-powered process control solutions support our customers’ sustainability efforts by efficiently controlling manufacturing drift, which can greatly reduce scrap wafers or the need for rework — both of which will minimize the use of process gases and electricity for tool operation,” said David Park, vice president of marketing at Tignis.
In addition, scrap can be reduced by improving some of the individual process steps in the fab. “The yields on these complex wafers, is going to drive up the amount of test time, which is naturally going to drive up the amount of power you consume on a per-chip or per-wafer basis,” said Mike Halblander, platform product manager at Teradyne. “What we can do is help them improve the yield. So even though you’re trading off some power, you’re gaining a higher yield with less less materiality scrap. So even if you’re consuming more power, you’re not throwing away half the wafer anymore. We have the test capability to help our customers do small operations, go back and laser trim and look at the results, go back and close the loop and say, ‘Okay, now it’s meeting spec. Therefore it doesn’t get thrown in the garbage.”
Water, chemistry and waste
Energy usage is a primary source of a factory’s carbon emissions. But various chemical gases used in the industry also have high associated CO2equivalent emissions, including many fluorocarbons used in etching processes. Sustainability also encompasses water usage and waste management.
During chip production, several million gallons of water are consumed daily, including ultrapure water for multiple cleaning steps, cooling and other applications. Water strategies typically target conservation and reclamation and may include investing in local water treatment. Standards assist companies in tracking progress.
UMC’s ESG 2022 report describes its efforts. “Affected by climate change and extreme weather, global water resources have become one of the most discussed topics, and often referred to as the fossil fuel of the next generation. Water resources are critical and essential in semiconductor manufacturing processes. Following the Business Water Footprint Accounting standards developed by international non-profit organization Water Footprint Network, UMC leads the industry in completing the water footprint verification of its 8-inch and 12-inch fabs in 2010. The assessment revealed that the direct water usage in UMC’s production exceeds that of the indirect supply chain. In response, the company has developed and implemented water conservation plans for its manufacturing processes. In 2022, third-party verification of water footprint (ISO 14046:2014) was completed using 8-inch wafers from Fab 8D and Fab 8E as the representative sample.” [5]
Sustainability is not just about conserving water. It also includes funding water restoration projects. By 2030, Intel plans for net positive water. “Net positive water is defined as water returned through water management practices, plus water restored to local watersheds, equivalent to >100% of our freshwater consumption.” [8]
Chemicals and materials used can be reduced, as well, and so can hazardous waste.
“On an ongoing basis, we utilize a significant amount of deionized water and monitor its quality and related city water consumption,” said Dick Otte, CEO of Promex. “Also, because we consume a fair amount of nitrogen, we have taken steps to improve its distribution within the building to eliminate leaks and minimize usage. Finally, over the years, we have modified, and we continue to monitor, our processes to eradicate generation of significant hazardous waste.”
Chemistry, though, presents the most challenging area to change. In wafer production, gases typically used in NF3, CF4, or SF6 have very high GHG emissions (see chart below).
Fig. 2: Semiconductor gases and their CO2 equivalents over a 100-year timeframe, including relative contributions of fluorocarbons and fluorinated gases. Source: imec [9]
Companies also are adopting improved abatement methods, but those come at the cost of higher energy use. Another option is new process development with alternative chemistries, which depends on time and collaboration.
Ann Kelleher, executive vice president and general manager of technology development at Intel, noted the specific challenges around chemistry and collaboration in a recent blog. [10] “Chemistry is critical to our industry — innovating to meet future regulatory impacts with greener and safer chemistry is imperative. A key part of our greenhouse gas footprint is the chemicals we use in our processes, many of which have spent 20 to 40 years in development. Finding suitable replacements for those could take a long time. This challenge isn’t unique to Intel. Our peers across the semiconductor manufacturing industry face it, too. That’s why we’ve committed to a cross-industry R&D initiative to identify greener chemicals.”
Progress
Progress is happening on all fronts. All companies reported reductions in CO2 emissions, like Brewer Science’s chart from its 2021 report. [3]
Fig. 3 Brewer CO2 equivalent emissions normalized to production volume. Source: Brewer Science
A sampling from a number of semiconductor manufacturers and suppliers’ reports illustrates the detailed tracking of progress across all areas.
Fig. 4: Selected examples of goals and progress made by a variety of companies. Sources: ESG reports
Companies are reporting numbers both for corporate governance reasons and because regulations are requiring more reporting. Over the next five years the industry needs to report on upcoming regulations.
“Our clients are focusing on preparing for various regulations worldwide, such as the Carbon Border Adjustment Mechanism (CBAM) [12], Corporate Social Responsibility Directive (CSR-D) [13], and Product Passport requirements in the European Union (EU) [14], as well as the pending SEC (Securities and Exchange Commission) decision,” said Genpact’s Dull. [15]
However, not all companies in the supply chain have the same goals; and most suppliers become Scope 3 sources for their customers.
“When it comes to a roadmap toward net zero, different companies have different goals. The system companies that are downstream have the most ambitious goals to become a net zero company by 2030 to 2040 timeframe. The semiconductor manufacturers and their goals are more in the 2040 to 2050 type of timeframe,” noted imec’s Rolin. “So there’s a tension, of course, because if a company like Apple wants to reach its 2030 net zero goal, it has to push its entire supply chain. Today they are actively pushing their supply chain to make progress along that front.”
Conclusion
For semiconductor manufacturers cost and performance has been the primary focus, but environmental impact is now a growing concern. “These environmental impact questions should become the affair of everybody,” said Rolin. “In the sense that we always look at performance, we will always look at costs. Today, it is also important that, on the same scale, we consider the environmental impact of what we are doing.”
The simultaneous growth in device demand and focus on sustainability is creating significant challenges. International demands on reporting and pressure from end system producers will be placing more and more emphasis on these matters. Companies are taking this seriously.
“We have continued to make meaningful progress over the last decade in reducing our environmental impact,” said Amkor’s Lee. “From setting our initial environmental goals, establishing a sustainability (now ESG) committee, and publicly disclosing climate change and water security information to the CDP (formerly the Carbon Disclosure Project), we have made steady progress toward more robust environmental stewardship. As we look to the future, we recognize the increasing importance of ESG matters for Amkor, and we are committed to advancing our ESG program, which is focused on sustainability and creating long-term value for our company.”
Given the inherent interdependency in the industry between suppliers, manufactures and system makers, no one company can mitigate environmental impacts on its own. To improve everyone, needs to work together.
References
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