Hermetic Glass-Thin-Film for Wafer-Level-Packaging of Sensors and ICs

Inhalt:
Borosilcate glass thin-films with a thickness of a few micrometers are used as dielectric passivation and as bond interface for anodic bonding of substrates. The glass thin-film enables direct hermetic passivation of semiconductors on wafer- level. For MEMS packaging the Lithoglas layer is replacing conventional glass wafers acting as anodic bondable layer when performing wafer-level capping of MEMS devices thus enabling stress compensated designs as well as further miniaturization of the devices - in our example for wafer-level integration of two silicon wafers. The new process allows for very moderate bond parameters with bond voltages in the range of 30 - 60 V at standard bond temperatures of around 300 °C and below. This enables the use of anodic bonding also for sensitive devices.