Micromachined Thermopile IR Detector Module With High Performance

In this letter, we describe a novel micromachined thermopile infrared (IR) detector module with filter and detector cointegrated by Au-Au thermocompression vacuum bonding technology. To miniaturize the detector module, both the thermopile IR detector and filter were fabricated by the silicon process, and the cap silicon wafer as the optical filter was bonded with the thermopile IR detector wafer in a base vacuum of 3 × 10^-5 millibar. Because the vacuum packaging reduces the gas convection, the wafer-level vacuum packaged thermopile IR detector module exhibits a 4 times higher response voltage than the atmosphere pressure packaged thermopile IR detector module. Using a sputtered pure thin Au layer as a bonding layer, average shear strength of 47.5 megapascals and leak rate of 3.9 × 10^-9 atm cc/s have been achieved, which guarantees the high reliability and good long-term stability of the vacuum packaged detector module.