Patent ID: 6593584
Filing Date: 2003-07-15
Classification: B82Y,H01J

Abstract:
A particle-optical apparatus which includes:(a) an object carrier (12) for an object (14) to be irradiated by means of the apparatus, and (b) an array (2) of particle-optical columns (4-i), each of which is provided with: at least one particle source (10) for producing a limited particle beam (8) of electrically charged particles, a focusing device (18) for producing a focus (16) of the particle beam in the vicinity of the object carrier, characterized in that the columns (4-i) are also provided with a beam limiting aperture (20) which is situated between the associated particle source (10-i) and the associated focusing device (18-i), and the array (2) of particle-optical columns (4-i) is subdivided into at least a first group of columns and a second group of columns, the columns in the first group being provided with a beam limiting diaphragm of a first diameter (22-k) and the columns in the second group being provided with a beam limiting diaphragm of a second diameter (22-m), said first and second diameters being mutually different.