| 摘要 |
PROBLEM TO BE SOLVED: To form a high precision nozzle hole without a cover and to enhance machining efficiency by making an aperture diaphragm variable in a projection optical system by which a nozzle hole having prescribed shape is formed on a substrate using a pattern mask and carrying out laser machining with a larger numerical aperture after carrying out laser irradiation with a prescribed aperture. SOLUTION: A variable aperture diaphragm AS for deciding a numerical aperture of a projection optical system is provided at the position of the entrance pupil of the system. Change in the diameter of the aperture is controlled by a driving device 42 through a control system 41, in which information concerning a substrate 30 is inputted as is information concerning a light source/illuminating optical system and change in the aperture diaphragm. In the formation of the hole HLL in the substrate 30, the numerical aperture NA1 of the projection optical system 31 is set for irradiation, in the manner that the laser beam wave length λ, hole diameter D to be formed, and the numerical aperture NAi of the illuminating optical system IL are set as Dx NAi/λ<=12 and NAi/NA1>=0.9. At the point of time reaching the number of a prescribed irradiation pulse, the numerical aperture NA1 is changed to NA2, with irradiation performed under the condition of NA2>NA1. |
