Research On Back-end Processes For Uncooled Infrared Detectors

Uncooled Infrared Detectors has shown a wide range of applications in military and civilian markets and has been a dramatic development in recent years. For typical MEMS devices, back-end process play an important role in protecting MEMS devices that can operation reliably. In the fabrication of infrared detector, the front-end process is mainly to make the detector chip, and the back-end is mainly to deposite membranes for enhance absorption and to implement detector package.In nitrogen atmosphere, black gold absorbers with the thickness of about ten microns is made by evaporation of gold. The results by scanning electron microscope show that the structure of black gold layer is sphere or fluffy cauliflower structures and are composed of clusters of nanometer-scale gold particles. Reflective infrared spectrum measurments show that the gold black film have high absorption in wide infrared spectrum which can significantly improve the absorption rate of detectors in the infrared and increase the response of the devices.Packaging process including the making of metal sealing ring on silicon substrate is researched by use of tin-lead electroplating method. Patterned metal sealing rings with about ten micons are successfully deposited and these patterned structures are bonded with shell of infrared detector by globe heating technology,Some meaningful results are obtained. This research is helpful for further reality of device vaccum bonding.