Electronic system packaging: the search for manufacturing the optimum in a sea of constraints

Manufacturing electronic systems is a multicomponent, multichip, hybrid design process which spans the life of the product. The design constraint list is not limitless, but if incomplete, can lead to economic loss for the product. Details of some of the constraints that affect system performance, reliability, materials selection, and the assembly of the product are presented. The electronic constraints include chip crossing delay, fan out (number of receivers on a driven net), crosstalk (unwanted electromagnetic coupling between independent signal lines and power supplies), DC voltage drop, the number of simultaneously switched line drives and reflections of signal waves from discontinuities in transmission line networks. The power dissipation constraints include maximum junction temperature, ambient temperature and pressure drop conditions, and component-to-component temperature variation. The cost constraints include materials, fabrication, and assembly. Some of the mathematical constraints are defined, along with the coupling between them and optimum solutions are shown graphically. The ability to resolve the system manufacturing constraints through optimization will determine the final success of a product