With the increasing demand for faster and denser integrated circuit devices, the need for high performance packages for commercial applications increases. Electrically and thermally enhanced quad flats (ETE-QFP) were developed to address the market's need for cost effective, high pin count, high performance devices. ETE-QFP's combine printed circuit board technology and heat slugs to increase package performance. Because ETE-QFP's are made with plastic, they are susceptible to a phenomenon known as "popcorn" cracking during surface mount assembly. This paper presents a moisture study using scanning acoustic tomography (SAT) to evaluate the impact of mosture on ETE-QFP's during the surface mount process. Data for the critical moisture percentage causing cracking are presented along with recommendations for storage and handling.
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