Patent Number: 044343710
Section: summary

TECHNICAL FIELD This invention is directed to an apparatus for deflecting electron beam sufficiently away from the normal beam path that the beam is blanked, and particularly apparatus for high speed beam blanking, together with the method by which high speed blanking of the electron beam is achieved. BACKGROUND OF THE INVENTION In high speed submicron lithography, an electron beam is focused and imaged toward its target. The target is a sensitive material which is exposed by the beam to permit different states of treatment of the substrate underlying the sensitive material. Usually the material is photosensitive which includes sensitivity to electron and/or ion beams. The beam is deflected to form a writing path on the target to produce an exposure pattern thereon. There are writing requirements which necessitate that the beam be blanked during certain parts of the deflection, in order to write separate patterns on the substrate. This invention is directed to high speed blanking which does not slow down writing or misdirect the beam during writing. There are two classes of electron beam equipment. In the first class, a small, high brightness electron source is focused, deflected and demagnified onto the target to produce a writing spot. This is considered to be a Gaussian beam because of the angular distribution of electrons from the high brightness source. The second class of electron beam equipment uses a source which floods an aperture to produce a specific beam shape. This flooded aperture is then focused, deflected and demagnified onto the target. In either case, a blanking deflector is positioned adjacent the beam to deflect the beam away from a blanking aperture sufficiently that little beam energy passes onto the target. The blanking deflector and blanking aperture thus achieve cutoff of the beam during non-writing portions of the operation. SUMMARY OF THE INVENTION In order to aid in the understanding of this invention it can be stated in essentially summary form that it is directed to an electron beam blanking apparatus for high speed blanking, and a method for high speed blanking. The apparatus comprises a tuned electrostatic and magnetic deflection unit which in the highest speed utilization is impedance matched with its transmission line and driver-amplifier. It is thus a purpose and advantage of this invention to provide an electron beam blanking apparatus and method which includes electrostatic and magnetic beam deflection, and also impedance matching to its driver-amplifier. Other purposes and advantages of this invention will become apparent from a study of the following portion of this specification, the claims and the attached drawings.