Worldwide Perspectives on SiP Markets: Technology Trends and Challenges

The market for stacked die and stacked packages is driven by portable applications that require extremely small form factors. System-in-package (SiP) has grown out of the need to incorporate increased functionality in smaller spaces. System-in-package (SiP) is a functional system or subsystem assembled into a single package. It contains two or more dissimilar die, typically combined with other components such as passives, filters, antennas, and/or mechanical parts. The components are mounted together on a substrate to create a customized, highly integrated product for a given application. SiPs may utilize a combination of advanced packaging including bare die (wire bond or flip chip), prepackaged ICs such as CSPs, stacked packages, and/or stacked die. Stacked die packages are one form of SiP and continue to see double-digit growth. The first stacked packages utilized in market applications contained only memory, but logic devices are being increasingly added. While the thinnest packages (important for mobile phones) feature bare die stacked inside the package, issues of bare die availability, logics, and test have resulted in a number of stacked package configurations. The typical mobile phone contains multiple stacked die CSPs, including some SiP (both memory and logic). SiPs are also found in personal digital assistants (PDAs), digital cameras and camcorders, laptop computers, and other portable products. SiPs are increasingly found in the RF, digital baseband, and transceiver sections of mobile phones. Some of these structures are planar constructions and several incorporate integrated passive substrates. SiP applications also include medical electronics such as smart pills and implantable devices, defense electronics, and aerospace applications. While these applications represent smaller unit volumes they represent higher value-added modules. Computer and telecommunication systems also use SiPs. These configurations typically feature a bare die surrounded by a packaged memory. The package-on-package (PoP) concept is being promoted by a number of companies, including Amkor. In this construction, one package is stacked on top of another. The assembly of the PoP takes place during board-level assembly. Skyworks ships SiPs in high volume using wire bond devices on a laminate substrate. Philips has developed a thin-film-on-silicon module that incorporates passive devices such as planar capacitors, pit capacitors, resistors, and inductors in the substrate. STMicroelectronics is shipping transceiver modules with an RF ASIC flip chip mounted on top of an integrated passive device. SyChip's module incorporates integrated passives in its thin-film-on- silicon substrate. Flip chip devices are mounted on the module to provide a "plug and play" solution for a WLAN application. Key challenges for wider acceptance of SiPs include availability of bare die and testing, logistical and engineering issues, wafer thinning, and assembly. Among the advantages of SiP solutions include smaller form factor, fast turn-time, and low NRE costs (compared to a single die design). Discussed are the various types of SiP in volume production, new technology developments and current challenges to wider acceptance of SiPs