Continuously volumetric dispense technology is perfect for the capillary underfill dispensing process. Underfill deposits a low viscosity fluid underneath a device – either a flip chip or a BGA. In both cases, the idea is to dispense a repeatable volume that will result in a uniform amount of fluid around all sides of the device.BGA Underfill with PCD Pump – video.
The capillary underfill dispensing process is conducted in a heated environment which, over time, reduces the viscosity of the fluid reservoir. For many types of dispense technology this reduction in viscosity greatly affects the amount of fluid and the amount of control the pump has over the fluid. With PCD technology, however, the volume of fluid in the individual rotor/stator cavities remains constant even when temperature changes are experienced during the underfill process. PCD technology will not drip or drool even when the reservoir is under 80 psi of constant pressure.Underfill has small fillers which can cause excessive wear to other types of dispense technology. Since the PCD pushes fluid rather than grinding fluid, the impact of fillers is significantly less. Customers running the system for more than 2 years in high volume environments have yet to report an issue with the volumetric capabilities of the pump. Rework and scrap product are greatly reduced by moving towards PCD dispense technology.
When dispensing underfill, a properly configured system yields a trouble-free, reliable process. Operator rework and scrap will be eliminated.
A typical system for underfill is configured with these additional options:
