A 16 element antenna integrated package for 37 – 40GHz operation

Antenna-integrated packages (AiP) at mm-wave address critical system-level challenges for large-scale arrays, promising higher performance, better integration, lower design complexity and cost. The reliability of mm-wave AiP must be studied and established to enable high-volume commercial deployments of large arrays with AiP unit-cells. In this work, we present a 16-element, 37-40GHz antenna integrated package (AiP) that is scalable to form large arrays. We focus on the package construction performance factors, such as co-planarity and reliability, which are critical for deployments in large volumes.The 15.2mm x 15.2mm size AiP was designed as package on -package (PoP), with a 2-metal layer top package for the antenna elements and a 10-metal layer bottom package for RF, digital and DC signal routing. An air gap was maintained between the top and bottom packages with a layer of solder balls. The antenna elements were designed as dual polarized, aperture coupled, patch antenna. The elements were placed in a 4 x 4 array, at a pitch of 3.85mm (1/2 wavelength at 39GHz). The AiP supported scaling to larger arrays with the AiP as a unit-cell enabling scalable, dense apertures at mm-wave. The peak gain of the 16 element array was 16dBi.A mechanical die identical in size, bump pattern and technology node to the functional die, and comprising electrical test structures, was used in preliminary reliability assessment. The antenna-integrated packages were assembled with the mechanical dice using the same process steps used to assemble the functional modules. The package co-planarity was assessed using Shadow Moiré technique. The component level reliability was assessed with high temperature storage (25 parts), moisture sensitivity level 3 pre-conditioning (50 parts), temperature cycling (25 parts) and unbiased highly accelerated testing (25 parts). The package met flatness requirements for Pb-free reflow profile, and passed electrical tests and CSAM inspections after 1000 hours in high temperature storage, 1000 cycles of temperature cycling and 264 hours of unbiased highly accelerated stress test. The results demonstrated the suitability of the AiP approach for large-scale deployments.