Method and structure for detection of electromechanical problems using variance statistics in an E-beam lithography device

A method of detecting electromechanical and mechanical errors in an electron beam device, comprising the steps of:

• providing a three dimensional gridlike subfield where each grid can be considered a target subfield;
• providing a plurality of target points on each target subfield for measuring combined directional variances;
• measuring separated x axis, y axis and z axis variances for said target points;
• completing significance tests for x axis, y axis and z axis values of said target points separately using Fstitch values;
• and
• comparing Fstitch values for x axis, y axis and z axis values and providing an error alert when there is a large disparity between said Fstitch values and a ratio of one.

An apparatus for providing automated detection of electromechanical and mechanical problems in an electron beam device, comprising:

• a gridlike subfield where each grid can be considered a target;
• a plurality of target points provided on each grid for measuring combined directional variances;
• a computational unit for measuring separated horizontal and vertical variances for said target points;
• significance testers for testing horizontal and vertical values of said target points separately and obtaining Fstitch values;
• and
• a comparator for comparing Fstitch values for horizontal and vertical values and an error alert component for providing an error alert when there is a large disparity between said Fstitch values and a value of one.