A method for testing a semiconductor wafer comprises providing a semiconductor wafer. The semiconductor wafer comprises a protruding annular rim, a first redistribution structure disposed on the front side of the semiconductor wafer, a second redistribution structure disposed on the rear side of the semiconductor wafer within the protruding annular rim and a plurality of vias extending from the front side to the rear side. A first probe is contacted to the first redistribution structure on the front side and a second probe is contacted to the second redistribution structure on the rear side. The first probe is in contact with the first redistribution structure and the second probe is in contact with the second redistribution structure at the same time.