A method for fabricating an interference display unit is provided. A first plate and a sacrificial layer are formed in order on a substrate and at least two openings are formed in the first plate and the sacrificial layer. A photoresist layer is spin-coated on the sacrificial layer and fills the openings. A photolithographic process patterns the photoresist layer to define a support with an arm. A second plate is formed on the sacrificial layer and posts. The arm's stress is released through a thermal process. The position of the arm is shifted and the distance between the first plate and the second plate is therefore defined. Finally, The sacrificial layer is removed.