QFPRework

QFPRework refers to the process of removing and replacing quad flat package (QFP) integrated circuits on printed circuit boards for repair, rework, or salvage. QFPs use leads on four sides and a flat body, offering high pin density but presenting challenges for reliable hot-air rework due to fine pitch and potential pad damage.

The workflow typically starts with preparation, including cleaning the area, applying flux, and preheating to reduce thermal stress. Removal is performed with a hot-air rework station using a controlled temperature profile and an appropriate nozzle to heat the QFP while protecting nearby parts. When the solder melts, the device is gently lifted with tweezers or a pickup tool; any residual solder on pads is cleared with flux and wick.

Replacement proceeds by aligning the new QFP, applying flux, and reflowing with a similar profile. After reflow, the board is cooled and inspected for solder bridges, insufficient joints, or pad lift. Excess flux may be cleaned, and the assembly is tested to verify function.

Common tools and materials include a hot-air rework station, a preheater or hot plate, compatible flux, solder wick, SMT tweezers, magnification, ESD protection, and correct-footprint QFPs or preforms. Underfill is rarely used for standard QFP rework, but may be added later for mechanical stability in some designs.

Quality considerations focus on controlling heat to avoid pad damage and component or substrate delamination, ensuring good joint reliability, and performing post-rework inspection and functional testing.