Advanced packaging and Integration Technologies for Microsensors

A novel sensor technology is suggested which has significant advantages in the areas of packaging and integration of sensors. It is proposed to develop this technology for pressure transducers. The key innovation of the process is the bonding of a sensor to a planar cover-wafer which contians through-wafer inteconnects. The sensor is hermetically sealed within the cover and is thus protected from the outside environment. The encapsulated sensor can be surface mounted to a header or board without external wires. This allows part of the packaging to be accomplished at the wafer level, enabling the benefits of batch fabrication to be applied to the package. The cover-wafer can also contain signal conditioning electronics to amplify and compensate the sensor's output. Integration is thus achieved at the wafer level, resulting in a reduced pin-count, which will lower the cost and improve reliability. This "smart sensor" is integrated vertically, thus allowing the independent optimization of the sensor and electronics with the coupling of the two.