Disclosed is an inspection method capable of performing an inspection of high reliability even for very fine and thin-film electrode pads of a target object, by using needle traces formed on the electrode pads and making the electrode pads repeatedly contact the probes at high accuracy. The at least one ballast tile has a first mounting member extending upwardly from a top surface thereof, the first mounting member configured to receive a lower end of a photovoltaic module. The use of an ultrasonic initial investigation operates as an initial evaluation point for the subsequent microwave investigation. Preferably, all of the components of the workstation remain connected to the workstation in the closed position and in the operating position, and no assembly is required.