Mounting of Surface Mount Components

Over the past few year, electronic products, and especially those which fall within the category of Consumer Electronics, have been significantly reduced in physical size and weight. Products such as cellular telephones, lap-top computers, pagers, camcorders, etc., have been reduced by as much as 3/4 of their original introductory size and weight. The most significant contributing factor to this reduction has been the inclusion of fine pitch, Surface Mount (SM) components. The larger, thicker and heavier leaded Through-Hole (TH) packages consumed far too much power, too much space and contributed significantly to the total weight of the final product. Product manufacturers were listening when the customer said ′′Make it smaller, lighter and less expensive′′. A second phase to this continued reduction in package size and weight is currently being experienced. A new family of sub-miniature surface mounted packages known under the industry’s generic name of Chip Scale Packages (CSP) have recently been introduced. CSP size components are currently the basis of a new series of consumer products. CSP components are currently being supplied in two (2) package configuration, both of which will be a maximum of 1.2 X of the die size. One incorporates planar or bumped pad interconnections on the peripheral of the package underside. The other package is in the form of a reduced scale ball grid array either in a partially or fully populated I/O condition. The increasing availability of the CSP significantly impacts the ability of product designers to design hand-held products of a size and weight not previously possible. The new CSP allows a higher density of components to be placed into an increasingly smaller portion of an existing printed circuit board, or that the printed circuit board may be reduced with an accompanying reduction in product size, weight and cost. Chip Scale Packages incorporating high I/O dies, along with discrete passive components are currently used in the design of the palm-sized camcorders. As a residual benefit, with components in closer proximity the signal propagation time is reduced thus producing a series of faster circuits. Accompanying the benefits of smaller size, reduced weight, higher density and increased performance, the individual Methods, Technologies and Techniques used to assemble printed circuit board assemblies have been impacted. Component Size Comparison