Ceos Corrected Electron Optical Systems Gmbh

Peter Schmid

Harald Rose

Roland Janzen

An electron-optical lens arrangement with an axis that can be substantially displaced, and useful for electron lithography, includes a cylinder lens and a quadrupole field. The plane of symmetry of the quadrupole field extends in the mid-plane of the gap pertaining to the cylinder lens. The focussing level of the quadrupole is oriented in the direction of the gap. The amount of the focussing refractive power belonging to the cylinder lens is twice as high as the amount of the quadrupole. A deflection system for the charged particles is connected upstream in the level of the gap pertaining to the cylinder lens and several electrodes or pole shoes, which generate a quadrupole field are provided in the direction of the gap pertaining to the cylinder lens. The electrodes or pole shoes can be individually and, preferably, successively excited and the quadrupole field can be displaced according to the deflection of the particle beam, so that the particle beam impinges upon the area of the quadrupole field. A holding device is provided for an object, such as a wafer, and is arranged vertically in relation to the optical axis and can be displaced in relation to the direction of the gap pertaining to the cylinder lens.

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Darmstadt, Germany

Peter Schmid