FlexiCoat Precision Spray Fluxing System

Sono-Tek is one of the originators of ultrasonic spray fluxing for selective PCB fluxing. With extensive expertise applying highly uniform thin films of flux to targeted areas with little overspray and no clogging, and have applied this experience in developing the FlexiCoat spray system configured for high volume Flip Chip fluxing applications. Ultrasonic spray provides a precise, repeatable, controllable spray solution for spraying flux onto contact pads, applying flux only to the required areas. The ability to spray very thin, uniform layers of flux prevents excessive flux residue, which can contribute to poor underfill, resulting in unreliable product. Having tight control of flux thickness also prevents die float, preventing downtime and poor die connections. Other methods such as jetting, dip fluxing, and pressure nozzle spray cannot apply thin targeted layers of flux. High throughput is achieved with automated XYZ motion and conveyor capability. Multiple nozzle configurations are possible to speed the spray process further.

Benefits to using ultrasonic spray for Flip Chip fluxing applications:

• Highly controllable spray avoids rework costs from overspray
• Ability to tightly control flux thickness of C4 flux area, with coatings as thin as 20 microns
• Thin flux layer eliminates die float which can result in scrapping of the die and substrate
• FlexiCoat coating system can easily receive JEDEC handling trays containing multiple substrate configurations
• 500×500 mm standard spray area, custom sizes available
• Fully automated PLC process control and recipe storage
• Alcohol in flux solution evaporates rapidly at room temperature, leaving the optimal amount of flux to hold the die in place during handling and reflow
• Non-clogging ultrasonic spray requires minimal cleaning and provides high repeatability, as spray performance is not compromised from gradual clogging experienced with pressure nozzles