Chankyu Kang

Gas cabinets are vital for safely handling high-pressure hazardous gases in semiconductor manufacturing, where rapid leak detection is essential to prevent safety incidents and production disruptions. Despite widespread use, conventional electrochemical sensors for gas leak detection respond slowly (30–60 s T90) and are limited by gas specificity, leaving a significant gap in universally effective and rapid detection for high-pressure releases. This study systematically investigates gas leakage characteristics in semiconductor gas cabinets, employing both full-scale experiments and computational fluid dynamics (CFD) simulations to understand how gas pressure, leakage angle, and leak position influence hazardous gas dispersion. Flow measurements and high-speed imaging identified the most significant leakage at the cabinet bottom, 135° angle, and 0.7 MPa pressure. CFD results validated against experimental measurements showed deviations within ±0.2 m s ⁻¹ . Simulations with silane and ammonia revealed that ammonia, due to its lower molecular weight and higher diffusion coefficient, dispersed more rapidly than silane. In argon gas experiments, the ultrasonic sensor consistently detected leaks within 0.4 s under all conditions; in contrast, the electrochemical sensor failed to respond at low pressures (0.15 MPa). Activation of the ultrasonic-linked interlock system effectively confined gas dispersion to within 1.1 m with maximum external concentrations of 0.012 ppm, compared to 70 000 ppm when using electrochemical sensors alone (CFD-validated). This work establishes validated performance benchmarks for ultrasonic-interlock systems, demonstrating prompt, reliable leak detection and containment that meets advanced safety management requirements in semiconductor facilities.

Objectives. This study examined fatal machinery crushing accidents in South Korea's manufacturing sector using official government investigation reports, identifying phase-specific vulnerability patterns and their policy implications. Methods. Analysis included 272 fatal accident reports (2016-2019) systematically coded through Reason's Swiss cheese model framework and interaction effect quantification using Cramér's V coefficients. Key variables comprise safeguard status, work phase, enterprise size, lock/tagout (LOTO) compliance and machinery type. Methods encompassed descriptive statistics, χ² tests and Cramér's V analysis, exposure-adjusted risk ratios and Pareto intervention simulation. Results. Among 132 legally mandated safeguard cases, 87.1% showed non-compliance, with 59.8% occurring during maintenance phases (safeguard-maintenance interaction: V = 0.35, p < 0.001). Small enterprises (Conclusion. Maintenance-phase systemic failures predominate through safeguard-procedure misalignment. Targeted interventions - mandatory LOTO audits, small and medium-sized enterprise support programs, priority machinery decommissioning - offer substantial fatality prevention. Findings inform Korean industrial safety policy while contributing phase-specific evidence to global machinery accident prevention.

Long-term hearing effects of occupational noise exposure below 85 dBA TWA remain insufficiently characterized in semiconductor manufacturing environments. This study evaluated longitudinal hearing-threshold changes among silicon wafer manufacturing workers exposed to moderate workplace noise over approximately 20 years. This retrospective cohort study examined serial pure-tone air-conduction audiometry (0.5-6 kHz) in 71 male semiconductor workers exposed to process-specific noise levels ranging from 72.2 to 80.9 dBA TWA. Participants were classified into normal-hearing (n = 53) and hearing-impaired (n = 18) groups according to Korean special health examination criteria and further categorized by manufacturing process: Process A (utilities), Process B (ingot processing), and Process C (wafer slicing). Longitudinal hearing-threshold changes were analyzed using repeated-measures ANOVA and compared with ISO 1999:2013 reference predictions. Both groups demonstrated significant deterioration in high-frequency hearing thresholds, particularly at 4-6 kHz (p < 0.001). Workers with normal baseline hearing showed threshold shifts of approximately 6-8 dB at 4 kHz and 8-10 dB at 6 kHz during follow-up, whereas workers with pre-existing hearing impairment demonstrated substantially greater progression. Process C, which had the highest recent exposure levels, showed the most pronounced longitudinal deterioration. Observed high-frequency threshold shifts were greater than conservative ISO 1999 reference predictions despite exposure levels below 85 dBA. Prolonged exposure to moderate occupational noise below current regulatory limits was associated with progressive high-frequency hearing deterioration in semiconductor manufacturing workers. These findings suggest that cumulative exposure duration and process-specific exposure characteristics should be considered in occupational hearing conservation programs.

Background: The rise of digital devices in the fourth industrial revolution has increased the demand for semiconductor safety. International Safety Certification Standards (SEMI) help prevent accidents in the semiconductor industry, but workers outside of Japan are still at risk. Objective: This study creates safety certification criteria for Korean semiconductor equipment by adapting SEMI standards, local laws, and technical guidelines to reduce facility-related risks. Methods: A self-certification system based on SEMI guidelines was developed through a global standard review, a manufacturer survey, and a Focus Group Interview to valid its applicability. Results: Japan uses a self-certification system, while other countries depend on SEMI, ISO, and IEC. To ensure domestic semiconductor equipment safety, aligning SEMI standards with Korea's Occupational Safety and Health Act. A survey showed strong reliability (a Cronbach's alpha value of 0.886) with 76.2% favorable and 4.8% unfavorable responses. Conclusion: This methodology allows Korea's semiconductor industry to comply with both domestic laws and SEMI guidelines, strengthening global trade and safety. However, the focus on a specific group of manufacturers and experts has limited research, requiring further validation in actual production environments. Future research should refine its practical application and expand to other high-tech industries.