PURPOSE: To obtain a membrane suitable to a mask substrate for X-ray lithography transferring and exposing a micropattern using soft X-rays, by forming a thin film by the plasma deposition metod, and removing the part except the part of the substrate to be made the frame.
CONSTITUTION: A 0.5W2μm thick Si3N4 film is formed on the substrate 1 as a thin film 2 to be made the membrane by applying electron cyclotron resonance plasma (ECR), and likewise on the reverse side of the substrate 1 a 0.2W0.5μm thick Si3N4 film 3 is formed. This film 3 is removed except the part to be made the mask pattern of the frame, and the silicon substrate 1 is etched off using the Si3N4 3A as a mask, while the part 1A to be made the frame is left alone. When a mask for X-ray lithography is prepared, an X-ray absorbing pattern 4 made of Au, Pt, W, Ta, or the like having high coefft. of X-ray absorption is formed on the membrane 1.
KIUCHI MIKIHO
SEKIMOTO MISAO
