A light transmission device is provided. The light transmission device includes a light source, a light transmission module and at least one light regulator. The light transmission module transmits a portion of the light of the light source for implementing a first semiconductor manufacturing process over the wafer. The light source is utilized to implement a second semiconductor manufacturing process over a wafer. The first semiconductor manufacturing process is different from the second semiconductor manufacturing process. The at least one light regulator regulates the light of the light transmission module transmitted to the wafer.