Converter and conversion method for converting a click position of a flat panel display into a light pen simulated signal for a semiconductor manufacturing machine are provided. A converter includes a first connector, a second connector, and a controller coupled between the first connector and the second connector. The first connector is configured to obtain the click position from the flat panel display. The second connector is configured to provide the light pen simulated signal to the semiconductor manufacturing machine according to a synchronization signal from the semiconductor manufacturing machine. The controller is configured to generate the light pen simulated signal according to the click position and a mapping table of a first display resolution of the flat panel display and a second display resolution of the semiconductor manufacturing machine. The first display resolution is higher than the second display resolution.