A Novel Filter Screening Methodology for Si Hardmask Materials in EUV lithography

摘要

The progression of EUV (Extreme Ultra-Violet) lithography into high volume manufacturing is driving the evolution of increased photochemical purity requirements. Further scaling will intensify the challenge to improve inline yield, ensure supply chain integrity, and increase reliability. Si hardmask materials play an important role in pattern transfer, and therefore require strict compositional materials integrity and stability to ensure expected performance. It is therefore critical to assess interactions between Si hardmask materials and components in the chemical delivery system to ensure hardmask materials purity and overall integrity. There has been an increasing demand on filtration technology to enhance material purity in semiconductor unit processes. Many efforts to improve filtration have focused on establishing retention ratings using various paniculate contaminants. While this is an important parameter to understand particle removal, it is equally important to understand the fundamental interactions between photochemicals and filters. As materials change and the smallest defects become even more challenging to detect, new filter screening methodologies are needed to address the most stringent defect targets. In this paper, a novel filter screening metrology is introduced to identify optimized filtration candidates for specific defect sources and improve defectivity in Si hardmask materials. Results and possible mechanisms of defect reduction will be discussed.