Wide area vertical expansion (WAVE^TM) package design forhigh speed application: reliability and performance

摘要

A two metal flex-based WAVE package has been developed to replacefour metal rigid based PBGA package. High board-level reliability wasthe primary motivation for this project and an equivalent electricalperformance was a challenging target. All the package dimensions weremaintained the same as the reference package to allow directreplacement. As a result of the one-year-long development program, therequired reliability and performance goals were met successfully. Thispaper mainly describes the WAVE package design for reliability andperformance. Optimal lead design is the most important step for reliablepackage development. The WAVE geometry model (WAVEGM) was developed toanalyze the lead type, lead orientation, bump height, and injection liftheight. The 2-metal flex tape was chosen to replace the original 4-metalrigid substrate due to its thinner dielectric layer, lower dielectricconstant and improved trace/space design capability. The electricalperformance was verified by both simulation and actual measurements of atest device