The semiconductor industry is a major driver of technological innovation but is also highly resource-intensive. As demand for microchips continues rising, understanding and addressing the resource consumption of semiconductor manufacturing becomes crucial. This article breaks down the major resources used in the industry, their importance, benefits, and environmental impacts.
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Vast Energy Powers Cutting-Edge Manufacturing
Semiconductor fabrication facilities (fabs) are among the most energy-intensive facilities in the world. According to a study published in Water Cycle, the semiconductor industry consumed 149 billion kWh in 2021- enough to power a metropolis of over 25 million people for a year.
An immense amount of energy is required for depositing material layers, etching intricate circuit patterns, doping, driving high-precision tools and cleanroom climate control systems and regulating ambient temperature and humidity to achieve nanometer-scale precision. The lower the node size - currently reaching 3 nm - the more energy is consumed per square millimeter produced.
The dominant energy sources for semiconductor manufacturing are grid electricity and fossil fuels, constituting 95.8% of total energy use. Renewable energy accounts for 2.7%, while other energy sources comprise 1.7% of the total energy consumption.
According to Greenpeace East Asia report, total electricity demand could reach 237 terawatt-hours by 2030 - over four times Australia's 2021 national consumption, leading to a corresponding increase in greenhouse gas emissions.
As a result, leading semiconductor manufacturing companies, like TSMC, Intel, and Samsung, have committed to 100% renewable energy procurement in manufacturing operations within the next decade.
Water Sustains Purity and Processes
Semiconductor production requires abundant water for cleaning chemicals and debris to prevent surface contamination, enabling chemical dilution and facilitating the crucial process of etching layers with atomic smoothness.
In particular, the semiconductor fabs use ultra-pure water (UPW), which has less than 1 μg/L total organic carbon and over 18 MΩ resistivity to ensure the high-quality manufacturing of semiconductors. Achieving this pharmaceutical-grade quality involves a thorough purification process, incorporating reverse osmosis, ion exchange, UV irradiation, and filtration.
A standard semiconductor fab consumes more than 5 million gallons of water daily. In 2021, major semiconductor companies globally utilized approximately 789 million cubic meters of water, with primary sources being surface water (47.0%), municipal supply (35.3%), groundwater (8.5%), and third-party providers (5.8%).
While much water gets reclaimed and reused on-site, high demand strains water supplies, especially in arid regions; for example, in 2020, TSMC utilized 193,000 tons of water daily, translating to an annual consumption of 70 billion liters, raising environmental concerns, particularly during Taiwan's recent drought.
Leading semiconductor manufacturers advocate using treated municipal wastewater or repurposing chip manufacturing wastewater for landscape irrigation. Simultaneously, they actively explore recycling and desalination options to address environmental concerns and optimize water usage.
Silicon - The Backbone of Semiconductors
Silicon has become the preferred material for semiconductor manufacturing due to its unique electrical properties and availability. Its electrical properties offer an optimal balance between conductivity and insulation required in microchips.
Furthermore, silicon offers excellent thermal resilience, operating reliably in temperatures ranging from -40 to 125°C. This allows silicon chips to function in diverse environments, from electronics under the hood of cars to consumer laptops and smartphones.
Silicon also suits high voltage applications as its relatively wide bandgap of 1.1 eV minimizes leakage currents. Its charge carriers additionally have higher mobility than other semiconductors, facilitating faster switching speeds.
Finally, the abundance of silicon in sand and quartz makes it inexpensive to produce in mass quantities necessary for the electronics industry.
Alternatives for Power Electronics
While silicon dominates digital logic applications, its properties prove less suitable for analog high-frequency electronics and optoelectronics. Alternative semiconductor materials such as gallium nitride (GaN) have gained significant interest in power electronics.
GaN's much wider 3.4 eV bandgap compared to silicon's 1.1 eV allows GaN devices to operate at voltages over ten times higher without avalanching. This facilitates smaller, more efficient power converters. Furthermore, GaN's electron mobility enables switching frequencies 100 times faster than silicon alternatives using the same voltage, saving dynamic power losses.
Specialized Chemicals Enable Microchip Fabrication
Semiconductor manufacturing would not be possible without a broad suite of hazardous chemicals. These include solvents, photoresists, wet and dry etchants, and dopants.
Solvents such as acetone, alcohols, and trichloroethylene are employed for cleaning organic residues and preserving delicate substrate layers. Subsequently, photoresists, comprising polymers and photoactive compounds, use selective light exposure to imprint circuit designs.
Wet etchants like hydrofluoric, sulfuric, nitric, and phosphoric acids selectively remove unprotected materials under photoresist masks, while dry plasma etchants reactively ionize exposed regions, typically with fluorine or chlorine gases.
Doping introduces impurities into the semiconductor crystal structure, enhancing its electrical properties and creating p-type and n-type semiconductors. The careful selection and distribution of dopants, such as boron, phosphorus, arsenic, and gallium, significantly enhance semiconductor performance, leading to faster, more efficient, and smaller electronic devices.
While these chemicals are essential, their improper handling poses environmental and health hazards. Developing less toxic alternatives remains a focal point in ongoing sustainable chemistry research.
Towards Greener Horizons: The Balancing Act for the Semiconductor Industry
Semiconductors are pivotal building blocks of the modern digital economy, but the substantial resources involved in their manufacturing cannot be ignored.
As industry leaders like TSMC, Samsung, and Intel plan ambitious expansions, environmental constraints around water, energy, and materials may present significant obstacles. The industry should, therefore, balance growth ambitions with intensified efforts to minimize resource consumption via efficiency gains, renewable energy adoption, lower-impact chemistry, and circular economy practices.
With smarter and more sustainable production, the semiconductor sector can continue propelling technological innovation for years to come.
References and Further Reading
Wang, Q., et al. (2023). Environmental data and facts in the semiconductor manufacturing industry: An unexpected high water and energy consumption situation. Water Cycle, 4, pp. 47-54. doi.org/10.1016/j.watcyc.2023.01.004
Wang, Q., et al. (2023). Water strategies and practices for sustainable development in the semiconductor industry. Water Cycle, 4, pp. 12-16. doi.org/10.1016/j.watcyc.2022.12.001
Brucker, V. M. & Jahn, F. (2023). Sustainability in the semiconductor industry. [Online]. Available at: https://www.knowledgeagent.de/blog/posts/sustainability-in-the-semiconductor-industry/
Greenpeace East Asia. (2023). Semiconductor industry electricity consumption to more than double by 2030: study. [Online]. Available at: https://www.greenpeace.org/eastasia/press/7930/semiconductor-industry-electricity-consumption-to-more-than-double-by-2030-study/
Mitchell, R. (2023). What Are Microchips Made Of: Silicon's Impact & Its Alternatives. [Online]. Available at: https://www.electropages.com/blog/2023/12/what-are-microchips-made
Sneci. (2022). Voltage in the semiconductor chemicals market. [Online]. Available at: https://www.sneci.com/blog/tension-in-the-semiconductor-chemicals-market/
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