Moisture ingress into organic laminates

The electronic industry's most common laminates (FR-4, HTFR-4, PI, CE, and BT) were investigated for their equilibrium levels of moisture and diffusion rates and monitored for their moisture content as a function of electrical capacitance. Isothermal sorption tests were performed on the laminates to find the equilibrium moisture content in each laminate at various environmental conditions. The moisture content of each laminate was evaluated as a function of electrical capacitance via a capacitance monitoring plate attached to each laminate. A model was developed to assess the equilibrium content as a function of both temperature and humidity. Data from the sorption-time experiments was used to evaluate a diffusion coefficient for each laminate. The Fickian model was used to facilitate the evaluation. The results of the laminate moisture content analyses were subsequently applied to a printed wiring board (PWB) with a capacitor plate on each of its laminates. The capacitance method of moisture measurement in PWB shows slower moisture ingress than the theoretical moisture diffusion based on laminate experiments     

Development of a multichip module DSP

The signal processor packaging design (SPPD) general-purpose digital signal processor (DSP) architecture is discussed. SPPD is a highly modular processor architecture that is based on off-the-shelf components and that supports a multichip module (MCM) design implementation that delivers 400 million floating-point operations per second in a 75-g package. The interconnect-substrate design, MCM package assembly, MCM testing, and tradeoffs in size, weight, and cost of the SPPD packaging are described