Patent ID: 7525109

Claim:
A method for writing a pattern on a specimen using an electron-beam (e-beam) tool having a positioning stage for moving the specimen in a plane substantially orthogonal to the e-beam, the positioning stage having a plurality of square-shaped fields arranged in an x-y Cartesian coordinate system and being capable of positioning each field with the e-beam, the pattern to be written defining a closed curvilinear path lying in a plurality of contiguous fields, the method comprising: writing with the e-beam first alignment marks on the specimen at the vertices of a first square-shaped field and second alignment marks on the specimen at the vertices of a second square-shaped field not contiguous with the first field, the first and second fields lying in the curvilinear path; writing the portion of the pattern lying within said first field on the specimen; writing the portion of the pattern lying within said second field on the specimen; adjusting, from the first and second alignment marks, the shape of an intermediate field between the first and second fields to provide a substantially continuous connection between said first and second fields by calculating the x and y offsets between the vertices of the first and second fields; positioning the shape-adjusted intermediate field with the e-beam; and writing the portion of the pattern lying within the shape-adjusted intermediate field on the specimen by scanning the e-beam to subfields within the shape-adjusted intermediate field using the calculated offsets to locate the e-beam to the subfields to thereby connect the portion of the pattern lying within the shape-adjusted intermediate field with the portion of the pattern in the first field and the portion of the pattern in the second field.