Complex microelectronic components, which have their contact area below the component (i.e. BGA) are mounted and contacted onto substrates using pick and place processes or even flip chip processes. To increase the bonding properties and to avoid contamination a process called underfill is used. Thereby, a viscous underfill material is applied close to the component edges. Capillary forces pull the fluid into the gap between component and substrate which generates the sealing.
Component underfill is one of the standard dispense applications at Häcker Automation. The portal system allows not only the exact positioning of the dispense head, but also an accurate movement of the dispense head along the component edges. The used dispense method ensures a constant material flow throughout the complete process. For an efficient underfill process it is essential to have the dispense needle as closely as possible to the component edge. The 3-D camera system recognizes precisely the component edges and corrects automatically even the smallest deviations in height and adjusts the position of the dispense head accordingly. In order to enable optimal underfilling results the substrate has to have an certain temperature. Therefore, a special heatable substrate carrieris available. Optionally the substrate can be adjusted with a dedicated fixture to optimize the position of the dispense needle to the component.
Technological challenges
Precise motion of the dispense needle along component edges
Uniform dispensing of underfill material
Applications
Flip chip assembly of ball grid arrays (BGA)
