Eco-Conscious, High Etch Rate, and Metal/Non-Metal Compatibility Stripper for Advanced Packaging Photo Resist and SOG
We report the development of an eco-friendly stripper tailored for advanced packaging and semiconductor processes involving thick-film photoresists. Conventional resist stripping commonly relies on solvent-rich formulations based on strong alkali (TMAH) and high-boiling polar aprotic solvents such as DMSO and NMP. In contrast, our design philosophy intentionally reduces environmental and safety burdens by employing a water-rich matrix (vs. low water contents in typical products), weaker alkalinity than TMAH via selected quaternary ammonium bases, and milder solvent systems with tuned polarity. The solvent package is engineered using Hansen Solubility Parameters (HSP) to optimize affinity with the resist film: we replace DMSO/NMP with a balanced mixture of polar and nonpolar solvents to achieve controlled swelling and dissolution from within the polymer matrix, thereby promoting simultaneous dissolution and lift-off while mitigating re-adhesion. Because weaker alkalinity could otherwise compromise deprotection and network cleavage, we compensate through molecular design of the alkali component—adjusting carbon chain architecture to enhance adsorption and affinity to resist domains—plus a specialty accelerator that restores stripping kinetics under reduced solvent content. As a result, the stripper demonstrates high removability across both positive and negative JSR photoresists and effectively covers resist films with differing crosslink densities and surface chemistries, delivering clean, re-adhesion-free surfaces.
Safety and tool compatibility have been primary requirements. All components are selected to avoid classification in toxicity hazard categories on the product safety data sheet, aligning with low-toxicity design practices established in JSR’s functional cleaners. The aqueous formulation exhibits good compatibility with standard single-wafer cleaning equipment and common tool materials (e.g., SUS, PP, HDPE, PTFE, polymeric parts, etc.), supporting straightforward fab integration. Beyond photoresists, the chemistry is extensible: it serves as a spin-on glass (SOG) striper by rapidly modifying the hydrophobic T-unit–rich surface layer to enable efficient room-temperature stripping for most SOGs, and—when mixed with hydrogen peroxide—functions as a remover for TiN hard masks while maintaining corrosion control of adjacent metals through tailored pH and inhibitor design. These capabilities derive from a broader framework that balances removal strength and substrate protection, leverages HSP-guided solvency matching, and employs adsorption-driven additives to prevent reattachment. Collectively, the stripper offers a practical pathway to lower solvent use, reduced toxicity, broad resist coverage, and multi-material applicability, supporting sustainable, high-throughput, and high-yield processing for advanced nodes and packaging.
BIOGRAPHY
Chihiro Kobata joined JSR Corporation in 2008, and he have focused on research and development of advanced chemical products for semiconductor manufacturing processes, including photoresist materials, cleaning solutions, and LED materials. From 2017, have specialized in cleaning technologies for leading-edge semiconductor manufacturing and been responsible for the development and customer support of cleaning solutions. From 2018 to 2023, relocated to the United States and worked at JSR Micro, and led research and development for cleaning solutions and CMP slurries, closely collaborating with global customers and process integration teams to achieve successful material qualification and commercialization.
Have extensive experience with semiconductor clean tools and analytical techniques for process evaluation and material optimization, with expertise in contamination control, metal residue removal, particle reduction, and surface condition analysis. Currently responsible for developing innovative cleaning solutions for semiconductor manufacturing processes. With over 15 years of expertise in semiconductor materials, continue to drive technological advancement to meet the evolving demands of the semiconductor industry.