A semiconductor manufacturing apparatus includes a leakage preventing device for preventing outward leakage of electromagnetic waves through an opening defined when a pod having a substrate accommodated therein is mounted on the semiconductor manufacturing apparatus. Fiber belts are wound onto these rings close to the rotor blades and include carbon fibers embedded in a high-temperature resistant polymer matrix. When the user specifies line step in the debugger statement, the debugger functions in true line step mode, where a line of source code is executed for each step.