A measuring method is provided. A probe and a first sensor are disposed over a jig including a bar protruding from the jig. The probe is moved until a first surface of the probe is laterally aligned with a second surface of the bar facing the jig. A first distance between the second surface of the bar and the first sensor is obtained by the first sensor. The probe and the first sensor are disposed over a magnetron. Magnetic field intensities at different elevations above the magnetron are measured by the probe. A method for forming a semiconductor structure is also provided.