Pollution and waste Semiconductor manufacturing is highly reliant on a diverse set of chemicals, resulting in pollution and waste. Half of the chemicals in manufacturing are in liquid form, creating wastewater pollution. A critical process to convert a wafer of silicon into a semiconductor involves several steps of layering chemical films (deposition) and projecting light (lithography) to create precise patterns. These chemicals often contain PFASs, with up to 163 different PFASs in use at any time across the industry. PFASs are known for their temperature resistance and being repellents of foreign material – these qualities make them ideal for semiconductor manufacturing; but the same qualities contribute to their status as “forever chemicals”, given their tendency to accumulate rather than naturally break down. Up to 5% of PFASs used during semiconductor manufacturing may enter the environment, with the remainder found in hazardous wastewater.155 In 2023, the 12 largest semiconductor manufacturers generated ~2.7 million tonnes of waste, equivalent to that of 5 million EU citizens.156 Half of this waste is classified as hazardous due to the waste metals and acids involved in manufacturing.157 While the majority of non-hazardous waste is combusted for energy or recycled for other industrial use, such as metallurgy or automotive manufacturing,158 recycling rates for hazardous waste vary substantially between companies, from ~20% to ~95%.159 Greenhouse gas emissions and electricity use Semiconductor manufacturing also produces direct GHG emissions. One concerning trend, shown in Figure A2 and covering 15+ years, is the ~160% rise in emissions per wafer as chips have got smaller and more powerful. The decrease in node size also drives a corresponding increase in energy use. This increase is primarily driven by lithography, a highly energy-intensive process that must often be repeated multiple times to create the layering needed for advanced chip design. Some manufacturers offset the impact of energy use by using renewable power, but this practice varies. Top performers use up to 90% renewable energy, while others use less than 10%.160 In some cases, renewable energy use comes through the use of credits and may not always be clearly reported. Power purchase agreements (PPAs) or on-site renewable generation more directly ties energy supply to demand. Semiconductor plants – emissions and energy use FIGURE A2 Energy/wafer (kWh)CO2e/wafer (kg) 02004006008001,0001,2001,4001,600 050100150200250300350 28nm ArFi 14nm ArFi 7nm ArFi 7nm EUV 5nm EUV 3nm EUV 2nm EUV CO2e/wafer Energy/wafer Note: Plant emissions are for manufacturing only. Source: Coles, S. et al. (2024). Putting a price on ESG risks. Barclays. Nature Positive: Role of the Technology Sector 57

Nature Positive Role of the Technology Sector 2025