Far IR sensing device and manufacturing method thereof

A far infrared (IR) sensing device includes a substrate, a light absorption layer, a sensing layer, a conductive layer, a plurality of pillars, an upper electrode, and a joint structure. The light absorption layer is disposed on the substrate, and the sensing layer is disposed in the light absorption layer. The conductive layer is disposed in the light absorption layer, wherein the conductive layer includes a lower electrode, a first support arm, a second support arm, and a connect portion for the upper electrode. The lower electrode is disposed below the sensing layer and is formed a continuous structure with the first support arm. The connect portion for the upper electrode is disposed below the sensing layer and is separated from the lower electrode, and the connect portion for the upper electrode is formed a continuous structure with the second support arm. The pillars are electrically connected to one end of the first support arm and the substrate and to one end of the second support arm and the substrat