Packaging and Integration Strategy for mm-Wave Products

Abstract

Abstract This paper is a follow on to the paper presented at the IMAPS 14th International Conference DEVICE PACKAGING and will provide more comprehensive case studies of few different system integration strategies for high frequency packaging. The packaging options vary widely based on the end market requirements, from performance, thermal, types and numbers of antenna arrays as well as the RF transceiver ICs. Tied closely to these performance related requirements is competing trade-offs of reliability, form factor and cost. We present assessment of packaging structures for (a) high performance mm-Wave network product and (b) consumer/mobile product and (c) automotive radar product. The former (a) is generally not challenged by form factor and can be enhanced by the addition of more antenna arrays and RFICs. However, care has to be taken to address the thermal solutions for effective heat dissipation as well as manufacturability issues as the package size may target ~400mm2 for Gen 1 and double or triple the area for subsequent generations. For (b), the primary drivers are cost and form factor. To manage antenna propagation and losses in a constrained form factor, mobile products generally require antenna in package (AiP) integration. The integration of the antenna within the same package as the RF IC greatly reduces the difficulty at the system level. This approach coupled to aggressive miniaturization of the antenna itself, using the same substrate technologies as the SiP leads to a new class of sub-systems termed Antenna in Package (AiP). This is extremely challenging from design, manufacturability and test perspectives. For example, Fan out wafer level packaging, such as eWLB packaging provides extremely smooth copper surfaces with tight etch tolerance compared to standard laminate based packaging. However, having multiport antenna structures fabricated in fan out technology with inductance matching and efficient ground ports, continue to be problematic. Hence adoption of 3D structures, in conjunction with SIP integration (with inductors and IPDs) can potentially provide relief. Inductors can also be built into the eWLB structure using the RDL as well as in the laminate packages using substrate embedded thin film cores.