There are different kinds of semiconductor manufacturing processes to be implemented on a wafer. Generally, different kinds of light sources are selected in accordance with the implemented semiconductor manufacturing process. For example, a WEE (Wafer Edge Exposer) module is utilized to expose the edge of the wafer. Generally, a WEE module includes a WEE lamp, a WEE housing and some optical parts. However, the WEE lamp, the WEE housing and/or the optical parts may have decaying intensities and short lifetimes. In addition, the maintenance and cleaning of the WEE lamp, the WEE housing and/or some optical parts require increased cost and labor. Therefore, there are still challenges in exposing the edge of the wafer in a more reliable and efficient way.