PURPOSE: To improve the quality without damaging an X-ray transmissive thin film to expose plating electrodes by a method wherein openings are made in the regions corresponding to the plating electrodes on resist patterns.

CONSTITUTION: An X-ray transmissive thin film 2 is formed on one surface side of an Si wafer substrate 1. Then, a primary thin film 4 and an electric plating conductive thin film 5 are successively laminated on the X-ray transmissive thin film 2. Next, resist patterns with regions 7, 8, 8' opened correspondingly to a region of X-ray absorbing patterns and the regions for plating electrodes 9, 9' are provided on the conductive thin film layer 5. Lead wires 10, 10' are connected to the plating electrodes 9, 9' through resist pattern openings corresponding to electrodes 9, 9' to fill the cavities between the resist pattern openings and the lead wires 10, 10' with insulating materials 11, 11'. Then, openings are made to electroplate the exposed conductive thin film layer 5 so that X-ray absorbing patterns 12 may be formed in specified thickness to remove the resist patterns 6 and the insulating materials 11, 11'. Finally, a part of Si is removed by etching process from the other side of Si substrate 1 to make a window.