An IC-centric biocompatible chip encapsulation fabrication process

Based on the requirements for miniaturization of a biocompatible package for medical implants, we derived a process flow for hermetic encapsulation of individual dies. In order to be cost-effective, wafer level based processing is used for this packaging flow. All processes are carried out using conventional clean room tools. Hermeticity of the individual dies or microsystems is ensured by using a stack of encapsulation layers, covering the individual dies. Furthermore, the die edges are sloped instead of straight, resulting in a better step coverage of the encapsulation layers. The total implantable device consists of various subdevices, hence assembly of these hermetical packaged subdevices is required, followed by a biocompatible metallization to connect the subdevices, and finally a global biocompatible embedding process is needed to obtain one single implantable device.