An Experimental Study of Atomization Characteristics of the Ultrasonic Spray Nozzle

The recent development in advanced packaging and MEMS applications has created a need for high aspect ratio lithography processes, ultrasonic spray coating is a very appropriate method to meet this requirement, the parameters of atomization are greatly affected the spray quality. By using a laser-phase Doppler analyzer (PDA), an experimental study was conducted of the atomization characteristics of the ultrasonic spray nozzle, water was used as the liquid to be atomized instead of photoresist and air was used as the auxiliary gas instead of nitrogen, the parameters of atomization characteristics under different operating conditions were measured, such as mean diameter D10 and diameter distribution of atomized droplet particles etc. The experimental measurement results indicate that the flow rate of atomized liquid and auxiliary gas have a significant impact on the spray characteristics, the nozzle can achieve a comparatively good atomization state under the condition of a relatively small flow rate of atomized liquid or a relatively high flow rate of auxiliary gas, the mean diameter D10 of droplets can be 18.39μm. The research findings can provide an underlying basis for the application of the ultrasonic spray nozzle.