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Area-array Assembly Line
The Area-array line features the assembly processes, materials and methods necessary for forming CSPs. The die-attach process shows the population of an organic strip containing multiple package interconnects with chip-on-board (COB) wire-bond die for the formation of CSPs. Processes featured include dispensing die attach and subsequent device placement with a single machine, curing the die-attach adhesive, plasma cleaning the wire-bond pad sites, ball-wedge gold capillary wire-bonding, dispensing high-purity COB die encapsulant and thermal curing the encapsulant material.
The ball-attach process includes the fluxing of the sphere pad sites with a tacky flux, the mass placement of eutectic solder spheres, reflow of the spheres (i.e., attaching the balls to the component body), aqueous cleaning of the balled devices, testing the devices, laser marking bad devices, extracting the devices from the strip carrier and vision sorting the devices by laser mark for placement into carrier tape.