Normal screen or stencil printing is next to impossible because the area around the repair site is restricted. To overcome this problem, Finetech offers a printing head for local and precise paste dispensing. The printing head is inserted into the reflow arm of a FINEPLACER^® system like a soldering head.

The procedure can be done quickly by moving the FINEPLACER^® system’s table: similar to placing components, the pictures of the stencil holes and PCB pads are brought into alignment. After this, the reflow arm can be lowered, and the solder paste printed with a manual squeegee.

The Direct Component Printing Module (DCP Module) ensures a simple, “All in One“ method for reworking QFN and MLF components. It is ideal for tight pitch QFN's, printing onto the component without disturbing the solder paste. When integrated into a FINEPLACER^® rework system, this module provides the one process step needed to create a reproducible, sequential solution.

The component contact pads are precisely aligned to the stencil and fresh solder paste applied directly to the component. The component is then transferred to the reflow arm and aligned to the substrate using the vision alignment system, accurate enough for even the smallest pitches.

Finetech offers both Side and Top Dispenser Modules.

The Side Dispenser Module provides the ability to precisely apply viscous media in controlled doses. The module can be used independently from the alignment system. Application of conductive glue is possible, after the chip has been optically aligned and without the need to shift the substrate. Dispensing of the viscous medium can be viewed using the optics of the alignment system. Since the alignment of the component is completed before dispensing, placement and bonding can be very accurate. The application of media after placement, e.g. for underfill, is also possible.

The Top Dispenser Module is capable of dispensing glue or solder paste onto the working plane of the FINEPLACER^®. The metering valve is a single-screw-extruder, the material to be dispensed is fed in typical dispenser cartridges and is administered by dispenser needles. Dispenser movements are realized by two computer-controlled pneumatic cylinders. Results can be observed through the main optic or, if present, a side camera.

For BGA rework and single ball reballing, tacky flux can be used to hold the solder balls in place during the reflow. Finetech designs custom solder trays to accommodate different solder ball heights. This simple device deposits flux on the bumps of a component and has three depressions, the depth of the depressions determines the amount of flux clinging at the bumps.