Ultrasonic Spray Systems for Photoresist Thin Films
Ultrasonic spray of photoresist in photolithography processes is an alternative to spin coating or vapor depositioning for thin film processing of MEMs or other semiconductor wafers requiring ultra precise uniform thin film coatings of photoresist into difficult areas such a v-grooves and deep vertical trenches. Ultrasonic photoresist spray enables fine tuning of process parameters for highly repeatable photoresist thin films.
Sono-Tek has been providing precision photolithography spray equipment for decades. Our new ExactaCoat system is ideal for smaller substrates requiring high precision, at a fraction of the cost of CVD or other vapor deposition equipment.
Several spray shaping options are available, depending upon coating requirements. Spray patterns range from 2 – 70 mm.
Ultrasonic nozzles feature up to 80% reduction in materials consumption, non-clogging performance, and precise, targeted spray patterns at ultra low flow rates.
ExactaCoat is ideal for depositioning thin films of photoresist prior to photolithography in applications where high precision and uniform layers are required. Ultrasonic nozzles are able to create unifomr thin films on arbitrary shaped or textured substrates more effectively than a high speed spin coating process.
The ExactaCoat system benefits:
- High aspect ratio comparable to or greater than conformal coatings.
- Uniform thin film coverage top to bottom of V-grooves, vertical trenches, and through silicon vias.
- Highly repeatable homogenous coatings.
- Low velocity spray avoids poor coverage from surface tension properties and ensures that resist adheres to substrate for proper edge coverage.
- Controllabe drop size depending on nozzle frequency.
- Economical alternative to spin coating, CVD, sputtering, and
electrodeposition processes. - Effective evaporation of solvent requires no additional steps for solvent removal.
When Precision Counts: Sono-Tek ultrasonic nozzles create a variety of precise spray patterns. Nozzles for photoresist applications are available in 2 operating frequencies – 120 and 180 kHz. Low velocity air is used to direct the atomized spray and create defined spray patterns.
Nozzles can be integrated with the following air shaping technologies:
