Ultrasonic Spray for Photoresist

There are a large variety of substrates that require the application of photoresist where conventional spin coating methods do not produce a uniform layer. The types of substrates include: wafers with various degrees of topography and micro vias, small glass lenses used for wearable devices, noncircular substrates, large panels, etc. The traditional spin coating method is often ineffective in applying a thin, uniform layer of photoresist to this class of “non-standard” substrates. The spin coating technique tends to clog the micro vias, will not produce a “conformal” layer to regions with high aspect ratio features, and has difficulty achieving a uniform layer to non-circular and large substrates. Additionally, spin coating generates significant waste of photoresist.

Ultrasonic spray coating for the application of photoresist to these non-standard substrates has proven to be a viable alternative to spin coating. Cheersonic ultrasonic nozzles are proven successful for dispensing photolithographic chemicals onto semiconductor wafers and flat panel displays. It is ideal for photoresist processes where high precision is required.

Benefits of ultrasonic spray for photoresist include:
• Uniform coverage inside deep well topographies such as MEMs.
• Reduction in photoresist consumption.
• Tight deposition density control.
• High transfer efficiency