The escalating emphasis on electrification and decarbonization of our society is causing an unprecedented surge in semiconductor fabrication. From powering electric vehicles to intricate functionalities of electronics and smart devices, semiconductors are a vital component driving technological advancements. Chemical-Mechanical Planarization (CMP) and wet etch processes are two critical operations to semiconductor manufacturing, and are ubiquitous across many different facilities. As a result of these polishing and etching processes, elevated copper levels are observed in the varying wastewater streams. These processes produce wastewater with different water quality characteristics which gives rise to complex and expensive treatment options to meet discharge compliance. As a result, the CMP streams typically employ expensive and wasteful solutions while the concentrated acidic copper streams produced from wet etching processes is typically trucked off-site for disposal. These solutions are unsustainable, and millions of pounds of copper are wasted every year in the US-based facilities alone.
In this presentation, we investigate the potential of a High Efficiency Selective Electrochemical Cell (HESEC) to recover copper from a variety of semiconductor wastewater streams while also achieving EPA discharge compliance. The copper chemical-mechanical planarization (CuCMP) and wet etch processes produce significant levels of copper laden wastewaters with complex matrices that make recovery of the copper difficult. Based on our experimental results the HESEC provides insight into how novel electrochemical cell designs can be used to achieve copper selective removal and recovery from different wastewater streams that open new possibilities for economical point source treatment and implementation of sustainable practices.
This approach underscores a comprehensive and rigorous approach to enacting a more sustainable wastewater treatment process. This process aligns with both compliance standards and sustainable environmental practices offering a holistic solution for the semiconductor industry. Future efforts will focus on deeper investigations of the different wastewater sources. Specifically, a collaboration with Lewis University will focus on slurry reuse possibilities and increase the current efficiency of the HESEC.