Nonuniformity-induced error in mask misregistration test structures

A performance comparison of two common misregistration test structures, the alignment resistor and the modified van der Pauw structure, incorporated adjacent to one another in a test chip for three separate fabrication runs, is presented. The results indicate that the modified van der Pauw structure consistently provides a more accurate measurement of the misregistration for the test structure sizes and fabrication process used. Errors introduced by lateral variation in sheet resistance and linewidth within each test structure are discussed