Laser-induced metal deposition for clear defect repair work on X-ray masks

By means of laser induced photolytic deposition it is possible to deposit tungsten spots with the same lateral dimension as predicted by the diffraction limit. Although the thickness of the deposited spots of about 1 mu m should be sufficient for X-ray absorption, the deposited spots could not be transferred into resist by X-ray lithography. The deposited material contains a certain amount of oxygen, which cannot explain the low X-ray opacity. Nevertheless, photolysis is more suitable for X-ray mask repair than pyrolysis, because there are no distortions due to heating of the thin membrane.