Electrostatic-Assisted Ultrasonic Spray-Coating for Nanotechnology Applications

Abstract

In this work we show a setup and optimized process of ultrasonic spray and electrostatic-assisted deposition of photoresist onto silicon substrates with deep etched areas. Drop size reduction at applied electric field is shown. The deposition of FP-3515 photoresist is conducted at a temperature of 45°C and provides good photoresist transfer and good film cleanness and quality. Deposition and drying of the photoresist layer is conducted simultaneously which implies uniform drying of the film and, thus, absence of mechanical strain. Another advantage is a possibility to create multi-layer coatings without partial dissolution of previously deposited layer. Deposited photoresist layer forms conformal film at edges and walls of deep etched silicon substrate. Maskless laser lithography has been conducted successfully that proved process practical suitability.