The invention relates to a preparation method of a micro-bridge structured
infrared detector, and a micro-bridge structure. The method comprises the steps that: a
metal reflective layer and a sacrificial layer are sequentially deposited on an
infrared detector readout circuit substrate; PI holes are etched on the sacrificial layer, wherein the PI holes are positioned at an out-leading
electrode of the readout circuit; a deposition support layer, a thermo-sensitive layer and a protective layer are sequentially deposited on the sacrificial layer; through holes are prepared in the PI holes, and a
contact hole is prepared on the protective layer;
electrode layer
metal is deposited on the protective layer, and U-shaped metals with bridge
pier structures are filled in the PI holes and the through holes; and U-shaped
metal structures are formed through
photolithography and
etching;
photolithography and
etching is carried out upon the
electrode layer metal; a
passivation layer is deposited on the surface of the device, and the
passivation layer is subjected to
photolithography and
etching, such that a
passivation layer pattern is formed; and sacrificial layer releasing is carried out, such that the micro-bridge structure is formed. According to the invention, a U-shape filling method is adopted, and Al is adopted as a filling material. Therefore,
sputtering and depositing are easy, and etching is convenient. The heat insulation property of the
detector is better than that of a
copper filling process, and a CMP step is not needed.