| 摘要 |
PURPOSE:To reduce an error in measurement of line width by generating light beams which differ in direction of polarization in a light transmissible material film and guiding them to one grating, calculating the wavelength of the light beams projected from the other at the same angle of projection, and calculating the line width from the relation among the wavelength, a propagation constant, film shape, and refractive indexes. CONSTITUTION:A film 1 which has a refractive index n1 and thickness (t) is sandwiched between a material 2 with a refractive index n2 and a material 3 (e.g. air) with a refractive index n0, and a grating 4 with a period S' and a grating 5 with a period S are formed on the surface of the film 1. Further, light 6 which has a different direction of polarization and wavelength lambda is guided in the film 1 from the grating 4 and the wavelength lambda of the light projected at the same angle theta of projection is measured. Further, the line width W is calculated from a relational expression which holds for the line width W, refractive indexes n0 and n1, etc. |
