Flip chip underfill system and method

摘要

A system (30) for dispensing a viscous material onto a substrate (16) which includes a dispensing element (22), a viscous material reservoir (20) and a metering device (25) coupled between the reservoir (20) and the dispensing element (22) for metering a variable amount of a viscous material through the dispensing element (22). The dispensing element (22) and metering device (25) can be moved by a positioner (32) along a predetermined pattern adjacent a surface of a substrate (16). A weigh scale (52) located adjacent the substrate (16) receives a metered amount of the viscous material and produces signals representative of a variable weight of the material dispensed during a predetermined time interval. A controller (40) adjusts a speed of movement of the positioner (32) along the predetermined pattern to cause the dispensing element (22) to dispense a desired amount of material based on a calculated flow rate. Alternatively, the controller (40) adjusts a rate of delivery based on the calculated flow rate.