Impact Of Lead Free Assembly On Laminate Electrical Performance For High Layer Count And High Reliability PCB
Authors: Deassy Novita, Ph.D., Gary Brist, and Gary Long Company: Intel Corporation Date Published: 10/13/2013
Abstract: Printed circuit boards in the high layer count server and networking segment are experiencing increasing demands on electrical and thermo-mechanical performance. Density, data rates, and Restriction of Hazardous Substances (RoHS) compliance are driving those demands. This paper details a portion of a High Density Packaging User Group (HDPUG) study which characterizes the impact of Pb-free assembly on laminate performance. Specifically, the impact of 6X 260C peak Pb-free reflow on the electrical performance of a variety of laminate materials used in these product segments is reviewed. The insertion loss and dielectric constant of the materials studied were examined before and after reflow conditioning of the test boards. The test boards for most of the materials were built with 2 different resin content constructions for comparison. The study quantified the impact of Pb-free assembly on the ability of multiple printed circuit board (PCB) laminate types (standard loss, low loss, halogen-free, brominated, mid-Tg, high-Tg, etc.) to maintain consistent electrical performance, and contrast the performance of the different materials.