Rework of BGA components

Area array packages are being increasingly used in the surface mount printed circuit board assembly domain due to their unique characteristics and high process yields. Several researchers have indicated that the process defects associated with the ball grid array components on printed circuit board assemblies are dramatically lower than those experienced with traditional leaded components. However, there are a number of other reasons to remove and replace components including package defects, engineering changes that are required after a number of components have been assembled, device or system upgrades, misregistration, wrong component orientation, etc. The rework of ball grid array components is a challenging task since the solder joints are hidden from view and cannot be readily accessed. Traditional approaches to rework that are applied to peripheral leaded or leadless components might not be applicable to ball grid array components. This paper provides a detailed discussion of the rework process for ball grid arrays. Topics that are addressed include the characterization of the rework system, nozzle design, the component removal process, the need for site redressing and the technique to be used, solder and flux application, and the component replacement process. A comprehensive set of process-related recommendations is provided for the rework of ball grid arrays.