Production-Proven Chemical-Free Green Alternative to Solvent and Piranha Wafer Processing using Ozone

Efforts to implement green technologies in semiconductor manufacturing have historically been slow with acceptance, blocked by perceived concerns over performance risk, operational disruption, and cost. Nowhere is this more apparent than in photoresist stripping, where aggressive chemistries like sulfuric-peroxide mixtures and hazardous solvents like NMP and DMSO remain standard, despite their well-documented environmental burdens. This paper presents a comprehensive assessment of a novel process that offers a rare and timely exception: chemical-free resist removal using ozone gas diffused through heated deionized water.

Unlike ozone-dissolved water systems this method operates in a high-temperature, ozone-rich gas environment. The result is rapid, surface-driven chemical deconstruction of the resist polymer, eliminating the need for persistent oxidizers or solvents, while producing minimal downstream contamination. Comparative lifecycle analysis across chemical input, energy use, waste generation, worker exposure, and effluent treatability reveals a substantial reduction in environmental burden—without compromising technical requirements. Measured CO₂e emissions per wafer are reduced by over 70% relative to sulfuric-peroxide and solvent-based strip methods. Tool-level performance data confirms comparability with common process chemistries, complete resist removal, and throughput on par with legacy methods.

The maturity of this process approach marks a departure from previous “green tech” proposals that failed to meet manufacturability thresholds. At a time when fabs face mounting pressure from hyperscaler customers, EU carbon regulation, and Scope 3 accounting mandates, this process uniquely aligns technical performance with immediate sustainability impact. Its adoption represents a meaningful step forward in closing the longstanding gap between sustainability goals and operational realities. 

The paper will first substantiate its environmental advantages through modeled CO₂e comparisons per wafer, based on documented chemical usage rates for conventional and ozone-based strip processes. It will then confirm the technical soundness of the method—grounding its effectiveness in known reaction pathways and supporting it with fab-level data on resist removal, compatibility, and defectivity. Together, these findings show that the process can be deployed now—without tradeoffs—to meet rising green manufacturing demands.