Aspects of the disclosure provide a method of tilting characterization. The method includes measuring a first tilting shift of structures based on a first disposition of the structures. The structures are formed in a vertical direction on a horizontal plane of a product. A second tilting shift of the structures is measured based on a second disposition of the structures. The second disposition is a horizontal flip of the first disposition. A corrected tilting shift is determined based on the first tilting shift and the second tilting shift.