Sea of leads (SoL) characterization and design for compatibility with board-level optical waveguide interconnection

Abstract

Sea of leads (SoL) is a novel ultra-high-density compliant wafer-level packaging technology. The x-y-z compliant input/output (I/O) leads are batch fabricated by simply extending wafer-level batch fabrication of on-chip multilevel interconnect networks. Two-port microwave measurements reveal that the leads exhibit an insertion-loss of less than 0.4dB in the 0.1-45GHz frequency range. In addition, worst-case insertion-loss of signal propagation into and out of the package is 1.15dB at 45GHz. Because the compliant leads are short, their electrical parasitics are minimal. A mixed-signal system-on-a-chip (SoC) requires packages that are compatible with optical interconnect technology. Physical design rules describing SoL design compatibility with board-level optical signal distribution via waveguides are derived.