Test structure for highly accelerated electromigration tests for thick metallization systems of solid state integrated circuits

摘要

A test structure and a process for the electromigration test of integrated circuits is suggested, in which metallization planes consisting of strip conductors of a usual thickness (11) are connected with metallization planes consisting of substantially thicker strip conductors (12) as they are required for the connection of components of higher performance.

主权项

1. A test structure for an accelerated electromigration test for thick metal strip conductors and for electric junctions between a thin metallization system (11) of a solid state integrated circuit and a thicker metallization system (12) of the solid state integrated circuit, both of which are disposed on the solid state integrated circuit, the metal thickness in the thicker metallization system being at least twice the metal thickness in the thin metallization system, the test structure comprising:
a first connecting island (1) and a second connecting island (1a) formed in the thicker metallization system; a first conductor piece and a second conductor piece (4, 4a) formed in the thin metallization system (11); a first power lead (2) for connecting the first connecting island (1) with the first conductor piece (4); a second power lead (2a) for connecting the second connecting island (1a) with the second conductor piece (4a); a test strip conductor (5) formed in the thicker metallization system (12); a first electric junction (3) for connecting the first conductor piece (4) with the test strip conductor (5) and a second electric junction (3a) for connecting the second conductor piece (4a) with the test strip conductor (5); and wherein the lengths of the first and the second conductor pieces (4, 4a) are dimensioned to substantially avoid electromigration of material from the first and the second conductor pieces caused by current for a specified current density to test the first and second electric junctions (3, 3a) and the test strip conductor (5).