| 摘要 |
PURPOSE:To make the width to be detected as a mark narrower than the width of the diffraction grating itself while preventing the minimum width of the grating element from lacking stability upon detection by making the length of each edge of multiple grating elements or the position of each edge in the elongation direction differ with respect to the orientation direction. CONSTITUTION:A plurality of grating elements 1a, 1b having edges, which contribute the diffraction and are parallel with each other, are regularly orientated in one direction so that those individual edges become parallel with each other. Further, the length of each edge or the position of each edge in the elongation direction is made periodically different with respect to said one direction, thereby forming a plurality of regions wherein the distribution of the diffracted light to be generated is different with respect to the width direction orthogonal to said one direction. For example, square (projected) grating elements 1a, 1b, the dimensions of which in the y- and x-directions are both B, are alternately arranged in the y-direction, thereby forming a diffraction grating 1. Moreover, the grating elements 1a, 1b are slightly shifted in the x-direction so that the row of the grating elements 1a and that of the grating elements 1b are overlapped with each other in the x-direction by a dimension D. |
