Wafer bonding

Service: Wafer bonding

Wafer bonding is a process for temporary or permanent joining of two or more wafers with or without an intermediate layer. Wafer bonding has various applications: packaging (e.g. for sensors and actuators), assembly (e.g. for RF components), integration (e.g. for electrical/micromechanical/optical components), and substrate and device fabrication.

The System Packaging department offers standard wafer level bonding technologies such as silicon direct, anodic, glass frit, thermo-compression, and adhesive bonding.  These technologies can be adapted according to the specific requirements (e.g. process temperature, yield, bond strength, and hermeticity) of target applications. 

Regarding service of wafer-level bonding, clean rooms with fully integrated process line including characterization equipment for the processing of 4"to 8" substrates are available at Fraunhofer ENAS.


Wafer bonding technologies are used for the the packaging of different sensor and actuator components, the fabrication of RF substrate materials and wafer level integration of electrical, micro mechanical or optical component. These technologies are continously optimized regarding their application parameters (e.g. temperature stability), yield and bonding strength. Other development approaches are given by the increasing diversity of materials in micro systems technology. Especially plastics, metals and ceramics are in the research focus to include aspects such as temperature, chemical resistance or low cost fabrication into product development.

To reduce device thickness, there is a trend towards thin wafers. With a thickness less than 50 µm the wafer becomes flexible and facilitate new applications e.g. the fabrication of through substrate vias (Through-Silicon Vias, TSV). The mechanical stabilization of such ultra thin wafers require new temporary waferbonding and debonding technologies. The department System Packaging is focusing on an adhesive temporary waferbonding technology to remove the device from the carrier wafer in a room temperature peel off debonding process after wafer thinning.

Regarding permanent and temporary bonding on wafer level, a full cleanroom preparation line including characterization equipment for 4" to 8" substrates is available.

Bonding Technologies:

The department System Packaging offers the following bonding services:

  • Silicon direct bonding,
  • anodic bonding,
  • glas fritte bonding,
  • eutetic bonding,
  • thermocompression bonding
  • adhesive bonding,
  • polymere bonding,
  • laser enhanced bonding and
  • reactive bonding.