Thermally enhanced FOWLP-development of a Power-eWLB demonstrator

Abstract

ID Number: 476) Current Fan Out Wafer Level Packaging (FOWLP) technology, eWLB, has limited heat dissipation capability, as the materials used in, namely the epoxy mold compound (EMC), originally aimed process ability and mechanical stability, but not heat conduction. As eWLB technology expands to WLSiP (Wafer Level System-in-Package) for very high system integration density, combining multiple chips and different components in the same package, the thermal performance becomes a critical factor. In a broader scope, the improvement of its heat dissipation capabilities opens eWLB technology platform also to power applications.A specific difficulty for all encapsulated packages is that the EMC must be electrical insulator, which places challenges both on heat conduction and on reliable mechanical bonding to a usually metallic heat spreader or integrated heat sink. Good heat conductors are, generally, electrical conductors and cannot be used as encapsulate materials. The EMC's are typically organic resins highly loaded with inorganic fillers, but high performance thermal interface material (TIM) are design for metal-metal interfaces, not for organic-metal as required.The paper describes the developments and results achieved towards a Power-eWLB demonstrator, using NANIUM's eWLB technology know-how and manufacturing capabilities. This demonstrator aims the improvement of thermal dissipation capabilities of a typical-size eWLB package, by using novel materials, adhesives and assembly processes suitable for high-volume production. It starts from baseline thermal characterization of eWLB package and the selected measurements methods; discusses the selected materials and techniques for the coupling of the WLSiP body to a heat spreader; and defines the 8mm x 8mm WLSiP capable of multi-pattern heating and dissipating up to 14W.The work done is part of the collaborative European FP7-ICT project NANOTHERM (Innovative Nano-and Micro Technologies for Advanced Thermo and Mechanical Interfaces), together with a consortium of leading IDM, OEM, OSAT, material suppliers and academic/ institutes. 978-1-4799-8609-5/15/$31.00 ©2015 IEEE

BME VIK Annual Research Report on Electrical Engineering and Computer Science 2015

“…The main task of our Department in this project is to help the industrial partners to optimize the thermal performance of the new interface materials, die attach layers and mold compounds [48,49]. This multi-scale task involves thermal performance tests -thermal resistance measurement, structure function analysis and thermal imaging -and reliability testing both on bulk material, subsystem and demonstrator level.…”

Development of Novel Low-temperature Curable Positive-Tone Photosensitive Polyimide with High Elongation

“…As the package size of integrated circuits (ICs) and pin-pitches of the devices dramatically decrease, the integrated multi-layered distribution technologies for IC chips have been developed due to their high performance, low fabrication costs, and miniaturization. Recently, dielectric materials for re-distribution layers (RDLs) have been focused on for the multi-pinned devices such as Fan-out Wafer Level Packages (FOWLPs), which is the one of the latest packaging trends in microelectronics [1][2][3]. There are a few requirements for dielectric materials as follows: the low-temperature curable nature (<250 °C) because the devices are embedded by the molded compound with low heat resistance, the strong adhesion to the copper RDLs, high chemical resistance, and high reliability in the multi-layered dielectric materials after the reliability test, for instance thermal humidity test, thermal cycle, and high-impact test, and so on [4].…”