On-Chip Voltage Generation for Scanning Electron Microscope Voltage Contrast Test Sites
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
By incorporating series-connected diodes into the test site, the voltage necessary to detect open-circuit conditions or localized high resistance points in wiring test patterns by scanning electron microscopy (SEM) is obtained. Thus, the necessity of wire bonding leads to the test structure and making connection to power supplies external to the microscope is obviated. Test preparation time is thereby greatly reduced. In very large-scale integration (VLSI) of semiconductor circuits, it has become a well-known practice to include test structures on product wafers for the detection of conductive line opens and very high resistance points. These defects often occur as the conductive lines go over etched edges in insulators as well as at contact points between wiring levels.