Identifying the Hazard Characteristics of Powder Byproducts Generated from Semiconductor Fabrication Processes
Semiconductor manufacturing processes generate powder particles as byproducts which potentially could affect workers’ health. The chemical composition, size, shape, and crystal structure of these powder particles were investigated by scanning electron microscopy equipped with an energy dispersive spectrometer, Fourier transform infrared spectrometry, and X-ray diffractometry. The powders generated in diffusion and chemical mechanical polishing processes were amorphous silica. The particles in the chemical vapor deposition (CVD) and etch processes were TiO2 and Al2O3, and Al2O3 particles, respectively. As for metallization, WO3, TiO2, and Al2O3 particles were generated from equipment used for tungsten and barrier metal (TiN) operations. In photolithography, the size and shape of the powder particles showed 1–10 μm and were of spherical shape. In addition, the powders generated from high-current and medium-current processes for ion implantation included arsenic (As), whereas the high-energy process did not include As. For all samples collected using a personal air sampler during preventive maintenance of process equipment, the mass concentrations of total airborne particles were < 1 μg, which is the detection limit of the microbalance. In addition, the mean mass concentrations of airborne PM10 (particles less than 10 μm in diameter) using direct-reading aerosol monitor by area sampling were between 0.00 and 0.02 μg/m3. Although the exposure concentration of airborne particles during preventive maintenance is extremely low, it is necessary to make continuous improvements to the process and work environment, because the influence of chronic low-level exposure cannot be excluded.