In-situ detection method for wafer movement and micro-arc discharge around a wafer in plasma etching process using electrostatic chuck wafer stage with built-in acoustic emission sensor

Abstract

We report an electrostatic chuck (ESC) wafer stage with a built-in acoustic emission (AE) sensor for detecting anomalies occurring around a wafer during plasma etching. The built-in AE sensor detects acoustic waves caused by wafer movement and micro-arc discharge with high sensitivity, and identifies these anomalies based on the frequency characteristics of the waves. The results demonstrate the effectiveness of using an ESC wafer stage with a built-in AE sensor for in-situ anomaly detection, which can improve the production yield and overall equipment efficiency in large scale integrated circuit (LSI) manufacturing.

Observation of prior light emission before arcing development in a low-temperature plasma with multiple snapshot analysis

“…As arcing occurs randomly in space inside a vacuum chamber, direct measurements of arcing signals such as voltage and current are impractical. Indirect methods have been adapted, such as measuring the voltage of the floating probe 19,20,24 , RF voltage/current of the powered electrode, emission spectrum of plasma 26 , and acoustic emission 27 . In this experiment setup, the AIP and additional bias were introduced to localized arcing.…”

Feasibility study of detection of dielectric breakdown of gate oxide film by using acoustic emission method

“…The dielectric breakdown is an extremely rapid phenomenon occurring on the order of µs and the AE signals also contain signals with rising and decay times of µs order; hence, highfrequency components are observed. 13) Accordingly, these results indicate that the AE sensor successfully detects the dielectric breakdown of the gate oxide film.…”

“…We have developed an acoustic emission (AE) method with a thin type sensor for the in situ detection of micro-arc discharge occurring around a wafer. [12][13][14][15] The thin AE sensor is composed of piezoelectric aluminum nitride (AlN) films, whose thickness is approximately 3 µm. A conventional AE sensor is typically 20 mm in height and 20 mm in diameter, whereas the thin sensor has a detector area of 1.5 cm 2 and is less than 1 mm thick.…”

Many flaked particles caused by impulsive force of electric field stress and effect of electrostriction stress in mass-production plasma etching equipment

“…20,21) The ESC wafer stage with built-in AE sensors can detect unusual wafer movement. 19,22) In order to measure the change in the floating potential when the plasma condition becomes unstable, a Langmuir probe is used. Signals from the VP-Probe, AE sensor, and Langmuir probe are simultaneously monitored by a digital oscilloscope with a sampling frequency of 1 MHz.…”