Patent ID: 6248486
Filing Date: 2001-06-19
Classification: G03F

Abstract:
A method of detecting aberrations of an optical imaging system, comprising the steps ofarranging a test object in the object plane of the system;providing a photoresist layer in the image plane of the system;imaging the test object by means of the system and an imaging beam;developing the photoresist layer, anddetecting the developed image by means of a scanning detection device having a resolution which is considerably larger than that of the imaging system,characterized in that use is made of a test object which comprises at least one closed single figure having a phase structure, and in that the image of this figure observed by the scanning detection device is subjected to an image analysis in order to ascertain at least one of different types of changes of shape in the image of the single figure, each type of shape change being indicative of a given kind of aberration.