Compliant wafer level package (CWLP) with embedded air-gaps for sea of leads (SoL) interconnections

Sea of Leads (SoL) is an ultrahigh I/O density (>10 ⁴ leads per cm ²) compliant wafer level package (CWLP) that potentially enables terabit on/off chip electrical bandwidth as well as enhances on-chip high current (e.g. >290 A) distribution of a mixed-signal system-on-a-chip (SoC). The addition of embedded air-gaps may mitigate problems with thermal expansion between the chip and printed wiring board, increase effective compliance of the package for wafer level testing applications, and reduce the dielectric constant of the interconnect dielectric material. An SoL package with 12000/cm ² leads has been designed and fabricated, along with a prototype SoL package with 1000/cm ² leads on top of a dielectric layer containing embedded air-gaps.