PROCESS FOR PRODUCING A SUBSTRATE FOR A REFLECTIVE OPTICAL ELEMENT FOR EUV LITHOGRAPHY

摘要

In order to counteract subsequent deformations, a process for producing a substrate for a reflective optical element for EUV lithography is proposed comprising the following steps: a block of material is provided; a surface of an area of at least 100 cm2 of the block of material is machined by stress-free material removal on the surface with a removal rate of at least 0.5 µm/h; the block of material is machined further. In preferred embodiments, before the stress-free machining step, the surface of the block of material is machined by stress-inducing material removal on the surface.