3D systems in-a-package (SiP)
Integration of wireless systems into a 3D cube shape is currently intensively adressed at IMEC through various European-funded projects RP035.
Within the project RP096 e.g., IMEC is applying its 3D-system-in-a-package knowledge to wireless sensor systems in cooperation with industrial partners. The solder ball interconnection technology results in much more compact heterogenous sensor systems compared to classical printed circuit board integration methods.
Figure 1 shows a prototype version of such a 3D-integrated system, using miniature connectors and including a compact rechargeable Li-ion battery. This module allows measuring acceleration in three axes (+-2g, a +-10g version also exists) with a high bandwidth (1250Hz). The replacement of existing wired sensors by compact wireless sensor nodes such as this will greatly enhance the flexibility for the partners' applications.
Figure 1: Prototype of a wireless sensor node measuring acceleration in 3 axes at a high bandwidth
Further research is ongoing on implementing the solder-ball based 3D-assembly techniques using completely lead-free materials C13065 and in a next step smaller volumes using 3D WLP techniques that are described elsewhere (see section 3D-WLP: micro-bumping), (see section 3D-WLP: ultra-thin-chip stacking (UTCS)).