Patent ID: 6072184
Filing Date: 2000-06-06
Classification: H01J

Abstract:
In a microlithography process in which a charged-particle beam is passed sequentially through individual subfields of a segmented mask so as to projection-transfer a pattern defined by the mask subfield-by-subfield through a projection-optical system onto corresponding regions on a sensitive substrate, an improvement comprising: when projecting an image of a mask subfield, of a segmented mask defining an (n+m).sup.th -layer pattern, onto a corresponding transferred pattern of an n.sup.th layer on the sensitive substrate, (a) measuring a rotational angle of the image of the (n+m).sup.th layer relative to the n.sup.th -layer pattern, and (b) correcting at least one of (i) a rotational angle of the image of the mask subfield of the (n+m).sup.th layer relative to the n.sup.th layer pattern, and (ii) a deflection direction of the image of the mask subfield of the (n+m).sup.th layer relative to an orientation of the n.sup.th -layer pattern.