International Business Machines Corporation

Luigi B Bassi

Paolo Spinzi

Stefano Sergio Oggioni

Michele Monopoli

Danilo Villa

Stefano O Oggioni

A volumetric pump for dispensing a controlled and continuous flow of viscous fluid. The pump according to a preferred embodiment of the present invention can ideally dispense from a minimum of 1 mg/sec to 1 g/sec for fluids with a viscosity from 2,000,000 cps (Centipoise) down to 10,000 cps. Such flexibility in the range of viscosity extends the application fields of this pump to microelectronics as well as automotive and consumer products manufacturing. Two cams mounted with an opposing position of 180&deg; on the same shaft generate an alternate motion of two concentric pistons. The alternate movement of the external piston in one phase pumps out the material through a dispensing needle and allows in the returning phase the viscous fluid to be charged in the dispensing chamber from the feeding container. The alternate movement opens and closes the vents during the different working phases.

Volumetric pump

A Plastic Ball Grid Array electronic package of the Cavity Down type particularly for use in high-frequency applications. In these packages the substrate has a cavity for receiving an active device (chip), which is usually attached to the substrate by means of the layer of glue. Due to the small dimensions of the chip and the gap between the chip and the cavity walls, it is extremely difficult to control the right quantity of glue in the dispensing operations. When the chip is pressed against the bottom of the cavity the glue may overflow and damage the circuits. According to the present invention, a secondary cavity is created inside the primary one and acts as a reservoir for the glue in excess.

Cavity-down ball grid array module

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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Lodi, Italy

Luigi B Bassi