## 1 Introduction  
Due to recent increase in demand for personal mobile devices, the scale of the semiconductor industry is expanding and competition among related companies is intensifying [1]. Accordingly, highly integrated chip production techniques on large-area wafers are rapidly being developed and applied as methods to increase the yield and profits of semiconductor companies. In the production of such high-performance semiconductor products, since the supply of high-quality silicon wafers is the most important requirement, an increasingly higher-performance wafer manufacturing process is required. For the fabrication of a high-quality wafer, the epitaxial growth process is used, which grows a desired single-crystal thin film on a wafer for application to a device [2]. This process requires a high level of chamber cleanliness because the influx of contaminated particles can interfere with single-crystal growth, leading to defects such as dislocation [3]. For this purpose, it is essential to identify and remove contaminant particles. Prior to that, various in-depth analyses are required through the measurement and collection of particles in the process facility [4]. Research and development of various equipment technologies have been conducted for the purpose of identifying particulate contaminants in semiconductor process facilities [5; 6]. However, due to extreme process characteristics, such as a high temperature and high vacuum environment and the use of corrosive and explosive gases, the actual implementation and application of real-time measurement and collection of particulate contaminants is difficult [7]. Currently, the best method is to collect and analyze particles detected on the substrate after the process or through the detection of particles remaining on the inner wall of the chamber by costly and inefficient dismantling of equipment [8]. Therefore, we attempted to introduce new measurement equipment based on the aerosol engineering principle not yet used for particle measurement or collection in semiconductor facilities. Another purpose of this study was to establish a corresponding method of application. A scanning mobility particle size (SMPS) classifies particles based on their electrical mobility and optically measures their numbers. It is a representative measurement device used for the measurement of particulate pollutants in the atmosphere [9; 10; 11; 12; 13; 14]. According to its operational principles, it has the advantage of obtaining an accurate particle size distribution (PSD). However, it is not possible to obtain PSD in every second because it has time resolution of 1-2 min for each scan/each measurement. For a PSD measurement at every second, a fast mobility particle size (FMPS) has been developed that can simultaneously measure the number of all particles using multiple electrometers [15]. However, since SMPS has been used and studied for a longer period of time with high reliability of measurement results, it is used more frequently even now [16]. Although these electromobility-based particle measuring instruments can measure particles with a size of at least several nm, they cannot measure particles of micron size due to their upper detection limits of several hundred nm. Using a different principle, an aerodynamic particle size (APS) and an electrical low pressure impactor (ELPI) that can measure PSD based on aerodynamic diameters of particles [17; 18] are also widely used. Of these two, ELII has the advantage of categorizing particles by size based on the multistage impactor principle, thus enabling real-time PSD measurement. It also has a wide measurement range from several nm to several \(\upmu\)m particles. In addition, it can facilitate additional analysis after collecting particles by size. Another excellent feature of ELII is its robustness, which makes it easier to use when collecting samples in very dusty atmospheres, which is not possible with either FMPS or SMPS [19].