International Business Machines Corporation

Paolo Spinzi

Luigi B Bassi

Michele Monopoli

Danilo Villa

A method for reworking a Ball Grid Array electronic module by removing the solder balls from the substrate surface after one or more of the connections have been detected to be damaged. The module is immersed in a water soluble oil bath and heated to the melting point. Then a rotating brush, with the rotating axis perpendicular to the substrate plane, removes the solder balls and the solder material particles while the module is still immersed in the fluid.

Reworking of a ball grid array module

A brushing system to be used in the manufacturing of electronic modules for removing unwanted particles from the substrate surface before the final encapsulation of the modules. The system provides an epicycloidal movement of the brush bristles on the substrate, which results in very effective in the removal of the particles. The system comprises a rotatable shaft with an eccentric bore. The hub of a rotatable brush can freely move inside the bore. When the shaft is rotated by a motor and the brush bristles are subject to friction, the brush describes an epicycloidal movement.

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Milan, Italy

Paolo Spinzi