A wafer-cleaning apparatus includes an inner pin that supports a wafer. The wafer-cleaning apparatus further includes a nozzle disposed above the inner pin, a light source disposed under the inner pin, a window disposed between the light source and the wafer, and a window protector disposed between the wafer and the window. The nozzle supplies a chemical liquid to the wafer and the inner pin distributes a portion of the chemical liquid on an upper surface of the wafer by rotating the wafer. The window protector receives a portion of the chemical liquid that flows out of the wafer and the light source supplies the light to the wafer through the window protector and the window.