Assembly of Area Array Components

Surface mount technology (SMT) has become the accepted standard for electronic assembly throughout the world. Surface mount packaging dominates the packaging industry due to the space saving and increased wiring capability achieved by directly mounting components on the surface of a board as opposed to the need for through holes in a printed circuit board (PCB). Cost, performance and ease of assembly have been the drivers in the trend away from DIP (dual-in-line package) packages and PTH (plated through hole) assembly to SMT. SMT packages include a variety of leaded and ball grid array packages all of which are mounted to conductors on the surface of a circuit card (Fig. 19-1). SMT assembly has increased dramatically over the past ten years typically allowing 1000-10,000 soldered connections per board as opposed to 250-4000 connections for similar through-hole assemblies. This chapter describes SMT assembly materials, equipment and process techniques in assembly of area-array or Ball Grid Array (BGA) packages including ball grid arrays (BGAs) and chip scale packages (CSPs).