Dispensing Mechanism
Non-contact fluid dispensing utilizes piezoelectric or pneumatic actuators to project discrete picoliter to nanoliter droplets onto target substrates. In advanced surface mount technology lines and semiconductor packaging, micro-drop jetting applies precise volumes of adhesives, flux, underfills, and conductive inks without mechanical needle contact. The dispense head operates at elevated frequencies up to several hundred droplets per second.
High-speed jetting eliminates the vertical z-axis motion required by traditional contact dispensing. Solder bridging and missing deposits are prevented by controlling droplet velocity and volume uniformity.
Process Advantage
Fluid velocity and drop break-off mechanics prevent satellite drop formation on dense assemblies. Because micro-drop jetting dispenses from a set standoff distance, it accommodates board warpage and uneven surface topography without risk of component collision. Cavity dispensing and tight keep-out zones benefit from narrow droplet trajectories.
Solder flux application before flip-chip placement achieves exact boundary definition without overspray. The jetting valve regulates viscosity through integrated fluid heating chambers, maintaining stable droplet mass despite ambient temperature variations. Viscous fluids like silver-filled conductive epoxies require optimized nozzle geometries to prevent clogging.
Quality Control
Optical inspection systems verify droplet volume and placement accuracy immediately following dispense cycles. Dispense mass calibrations rely on analytical micro-balances to measure dispensed dot weight over production lots. Nozzle clogging or fluid cavitation causes volume starvation and defective component bonding.
