Patent ID: 6980304

Claim:
A method for measuring a characteristic dimension of at least one pattern on a disc-shaped object in a measuring instrument, the measurement instrument having a lens system and a computing and control unit, the at least one pattern being formed in at least one fabrication step and subsequently being checked by the measurement, comprising: measuring at least one alignment mark for aligning the provided disc-shaped object relative to the lens system of the measuring instrument; measuring the at least one pattern in order to detect the at least one pattern on the disc-shaped object; measuring the at least one pattern in order to set the lens system to achieve a sharp image of the at least one pattern; and measuring the characteristic dimension of the at least one pattern, wherein at least one of the measuring steps is assigned in each case a parameter and in each case a computing rule for determining a value for the parameter, which represents the quality of the measuring step respectively carried out, a limiting value is assigned to the parameter, the computing and control unit applies the computing rule to calculate the value of the parameter from the measured data obtained in the at least one measuring step, the computing and control unit compares the calculated value of the parameter with the assigned limiting value, and at least one of the fabrication steps required to form the pattern is repeated for the disc-shaped object in the event of overshooting of at least one of the limiting values.