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 first interface circuit is configured to communicate with the flat panel display to obtain the click position. A second interface circuit is configured to communicate with the semiconductor manufacturing machine to obtain horizontal and vertical synchronization signals. A memory is configured to store a first display resolution of the flat panel display and a second display resolution of the semiconductor manufacturing machine. A processor is configured to obtain the light pen simulated signal according to a light pen position corresponding to the click position and the first and second display resolutions and to control the second interface circuit to provide the light pen simulated signal to the semiconductor manufacturing machine according to the horizontal and vertical synchronization signals.