Method of Localizing and Analyzing Gate Oxide Defects
Original Publication Date: 1988-May-01
Included in the Prior Art Database: 2005-Feb-15
A method is described which localizes and analyzes even minimum gate oxide defects in MOS structures. The test structure, used for this purpose, consists of gate oxide lands interconnected by narrow aluminum conductors. By repeatedly halving the test structure and testing the halves thus obtained, gate oxide defects in areas as small as 10 x 10 mm can be localized and analyzed at low defect density. (Image Omitted) As the integration density of VLSI circuits increases, the density of gate oxide defects has to be reduced accordingly. At a defect density of, say, 0.2 per mm2, this means that test structures with a total area of 5 mm2 have to be tested, to detect on an average one defect.