REWORK OF BGA COMPONENTS

Area array packages are being increasingly used in the surface mount p rinted circuit board assembly domain due to their unique characteristi cs and high process yields. Several researchers have indicated that th e process defects associated with the ball grid array components on pr inted circuit board assemblies are dramatically lower than those exper ienced with traditional leaded components. However, there are a number of other reasons to remove and replace components including package d efects, engineering changes that are required after a number of compon ents have been assembled, device or system upgrades, misregistration, wrong component orientation, etc. The rework of ball grid array compon ents is a challenging task since the solder joints are hidden from vie w and cannot be readily accessed. Traditional approaches to rework tha t are applied to peripheral leaded or leadless components might not be applicable to ball grid array components. This paper provides a detai led discussion of the rework process for ball grid arrays. Topics that are addressed include the characterization of the rework system, nozz le design, the component removal process, the need for site redressing and the technique to be used, solder and flux application, and the co mponent replacement process. A comprehensive set of process-related re commendations is provided for the rework of ball grid arrays.