Toray Research Center Launches High-Sensitivity Analysis Service for Nanoparticles in Chemical Solutions to Support Growing Semiconductor Demands in the AI Era

【Abstract】 Toray Research Center, Inc. (Location: 1-7-2 Nihonbashi Honcho, Chuo-ku, Tokyo; President: Yoshiki Makabe; hereinafter referred to as "TRC") has developed a technology capable of analyzing the particle concentration and size distribution of impurity metallic nanoparticles, a problem in semiconductor manufacturing processes, with the highest sensitivity in Japan. This was achieved by highly optimizing the sample preparation methods and measurement conditions for single-nanoparticle inductively coupled plasma mass spectrometry (spICP-MS※2), utilizing an inductively coupled plasma mass spectrometry※1 instrument. Leveraging this technology, TRC is launching a contract analysis service targeting nanoparticles in chemical solutions for semiconductor manufacturing. As semiconductor miniaturization progresses, even trace amounts of nanoparticles in the nanometer※3 size range can cause defects such as disconnections and short circuits. Therefore, purity control of chemical solutions used in the manufacturing process is becoming increasingly important from the perspective of ensuring yield. spICP-MS is a highly sensitive analytical method that can detect and simultaneously measure the size and particle number concentration of metallic nanoparticles present in liquids, one particle at a time. By constructing a unique analysis system that maximizes the features of this method, TRC has made it possible to detect and quantitatively evaluate extremely trace amounts of impurity nanoparticles contained in chemical solutions. This service is expected to contribute to further high-purity chemical solutions and improved yields in advanced semiconductor manufacturing. 【Background】 Amidst advancements in semiconductor performance and power efficiency, device miniaturization is accelerating further. On the other hand, contamination by metallic nanoparticles is a growing concern as a cause of disconnections and short circuits in integrated circuits. Various chemical solutions, such as photoresists※4, acids, and organic solvents, are used in semiconductor manufacturing processes. The impact of impurity metallic nanoparticles contained in these solutions on device reliability and yield cannot be ignored, and there has been a strong demand for technology that can sensitively and quantitatively evaluate extremely trace amounts of metallic nanoparticles in chemical solutions. spICP-MS is an analytical method capable of detecting metallic nanoparticles dispersed in liquids even at extremely low concentrations of a few ppt※5 (one part in ten billion), making it effective for evaluating impurity metallic nanoparticles in chemical solutions. However, challenges have existed in detecting trace and minute particles due to the influence of noise signals originating from impurities in reagents used for sample preparation, metals ions and contaminants in the sample, and contamination within the measurement instrument, as well as sensitivity fluctuations caused by slight differences in measurement conditions. 【Technology and Analysis Example】 In response to these challenges, TRC has built an analysis system that maximizes the features of spICP-MS by combining high-purity solvents for sample preparation, operational management to maintain a clean instrument environment, and optimization of measurement conditions tailored to the chemical solutions and particles being analyzed. As a result, it has become possible to sensitively and stably detect and evaluate extremely trace amounts of metallic nanoparticles present in chemical solutions for semiconductor manufacturing.

As an example demonstrating the effectiveness of this technology, Figure 1 shows the results of analyzing impurity metallic nanoparticles in propylene glycol monomethyl ether acetate (PGMEA※6), which is used as a solvent for photoresists and as a cleaning agent in semiconductor manufacturing processes, using spICP-MS. When commercially available high-purity PGMEA was measured as is, numerous metallic nanoparticles such as aluminum (Al) and iron (Fe) were detected. This result indicates that metallic nanoparticles exist as impurities even in chemical solutions generally considered "high-purity." When sample preparation is performed using this PGMEA, it is difficult to distinguish whether the detected particles originate from the sample or from the PGMEA used in preparation. On the other hand, when a similar analysis is performed after purifying this solvent, metallic nanoparticles are hardly detected, demonstrating that more sensitive and reliable impurity evaluation is possible by using appropriately purified reagents. Furthermore, the Fe particles detected from the purified PGMEA correspond to a concentration of 0.04 ppt in the solvent, achieving extremely high detection sensitivity. Additionally, this method enables the evaluation of metallic nanoparticles contained in resins by dissolving them in an appropriate solvent, making it effective for estimating contamination sources in chemical solutions derived from solid resins. The analysis of extremely trace amounts of metallic nanoparticles in resins has become possible for the first time by using a purified high-purity solvent for resin dissolution. TRC plans to expand the scope of application to various solvents and materials in the future to meet a wider range of analytical needs. <figure class=