| 摘要 |
PURPOSE:To achieve that recesses parts in an alignment mark are made substantially symmetric with respect to a beam of light for position detection use and to reduce the detection error of the title apparatus in an alignment operation by a method wherein the width in an alignment direction of the recessed parts in the alignment mark is set to be narrower than the length of three times the wavelength of the beam of light for position detection use. CONSTITUTION:The width (d) of recesses parts 2b in a wafer mark is set to be narrower than the length 3lambda (or 3lambda/n) of three times the wavelength lambda of laser beams LB1, LB2 as beams of alignment detection light. At the inside of the recesses parts 2b, the laser beams LB1, LB12 are attenuated exponentially and hardly reach the bottom part. Consequently, even when a difference in level DELTAh1 is caused at the bottom of each recessed part 2h and the wafer mark becomes asymmetric in the X-direction, the wafer mark is equivalent to a symmetric mark with reference to the laser beams LB1, LB2. Consequently, a measured result by means of the laser beams LB1, LB2 becomes accurately the position of the mark and the detection error of the title apparatus is not caused. |
