Patent ID: 7388213

Claim:
A method of improving registration of a particle-beam relative to a non-exposed, photoresist-coated substrate, wherein at least a portion of the registration targets are present within an area of the non-exposed photoresist which is to be imaged during patterning, said method comprising: a) providing a primary beam optical axis in the form of a particle beam axis, wherein said particle beam is used to generate a pattern; b) providing a secondary optical axis in the form of an optical reader axis; c) providing a position fiducial at a fixed location relative to the substrate; d) providing a controller adapted to control the operation of the particle beam axis and the optical microscope axis, wherein the controller is also adapted to calculate a plurality of vectors from the position fiducial to a plurality of pattern alignment targets present on the substrate; e) using the secondary optical axis to determine a feature location of the position fiducial, and calculating coordinates x 0 y 0 of the feature location; f) moving the substrate under the secondary optical axis such that an alignment target is within a field of view of the secondary optical axis, and calculating coordinates x 1 y 1 of the alignment target location; g) calculating an alignment vector for the alignment target, which vector is l 1 =(x 1 −x 0 )x+(y 1 −y 0 )y; h) calculating at least 2 additional alignment vectors for at least 2 additional alignment target locations using steps f) and g); i) moving the position fiducial under the primary beam optical axis, and scanning a feature of said position fiducial using the primary beam optical axis in a manner to determine the location of the position fiducial; j) calculating coordinates (x′ 0 , y′ 0 ) of the position fiducial for the primary beam optical axis; and k) calculating a location for previously-determined alignment target locations on the substrate with respect to the primary beam optical axis, by applying corresponding location vectors l n , where n is an integer of at least three, to the coordinates (x′ 0 , y′ 0 ) which represent a starting location of the primary optical axis, whereby the primary optical axis is registered to the pattern alignment targets on the non-imaged photoresist coated substrate.