Abstract: To remove small particles from surfaces of solid bodies at least one laser pulse of high power density (excimer laser) is directed onto the surface. The method is particularly suited to clean Si-masks used in electron-beam lithographic devices. An arrangement for in-situ-cleaning of masks in accordance to this method is integrated in such an electron-beam lithographic device.

Abstract: A mask for radiation beam lithography is formed from a semiconductor wafer by thinning a region into a membrane with a hole pattern defining the pattern of the mask. The membrane is doped with a tensile stress-generating material so that minimum doping exists at the periphery of the membrane with the maximum at its center. The difference in doping between the periphery and the center is chosen so that when the mask is irradiated with a given beam current intensity, the membrane is tension-free. To make a mask in the wafer, a hole pattern is formed by etching holes in the membrane or by depositing a layer on the membrane. The wafer is thinned from the opposite surface until the holes in the hole pattern are throughholes or until the desired thickness is reached. The membrane is doped with tensile-stress-generating material using ion implantation or diffusion proportionally to the temperature distribution existing in the membrane during irradiation with exposure beams.