| 摘要 |
PURPOSE:To manufacture a phase shift type diffraction grating whose shape is excellent with good reproducibility by canceling the aberrations of an optical system by using a phase conjugate mirror. CONSTITUTION:Laser light from one He-Cd laser is split into two by a beam splitter and passed through beam expanders respectively to generate luminous flux 6 and reference luminous flux 13. Then, a phase plate 1 which makes a desired phase shift is irradiated with slantingly incident parallel light 6 and the transmitted wave 7 from the phase plate 1 is made incident on a half-mirror 2. The transmitted wave 8 from the half-mirror 2 is converged through a lens 3 on the phase conjugate mirror 4. The reflected wave 10 from the conjugate mirror 4 is made incident on the lens 3, whose transmitted wave 11 is made incident on the half-mirror 2. Part of the transmitted wave 11 is made into parallel luminous flux 12 through the half mirror 2. The luminous flux 12 and reference luminous flux 13 are caused to impinge on a semiconductor substrate 5. Thus, the light is made incident on the conjugate mirror 4 once and the reflected luminous flux 12 from the conjugate mirror 4 and the reference luminous flux 13 are interfered with each other to compensate the aberrations. |
