Development of in-situ particle monitor with beam homogenizing module for enhancement of nanoparticle countering efficiency

Abstract

An in situ particle monitor (ISPM) was developed to measure the concentration of several hundred nanosized contaminant particles generated from the semiconductor process. It is difficult to measure particles below 300 nm owing to low sensitivity and reliability. To improve the sensitivity and reduce the uncertainty caused by the Gaussian distribution of laser, a beam homogenizing module was applied to transform the Gaussian beam into a flat-top beam by total internal reflection. The performance of the beam-homogenizing ISPM was evaluated by measuring standard polystyrene latex particles in vacuum. We analyzed the measurement efficiency by a comparative evaluation with a scanning mobility particle sizer. Following this, the count of particles generated from the exhaust line of a plasma-enhanced chemical vapor deposition process was measured for real-time process diagnosis.

Digital pulse analyzer for simultaneous measurement of pulse height, pulse width, and interval time on an optical particle counter

“…A Gaussian shaped pattern was also found using an OPC made by Gao et al [12]. This pattern might be occurring due to the Gaussian profile of the light source, caused by the transverse electromagnetic mode [36] and uniformity [37].…”