EFFECT OF INTERFACE LAYER ON THE MICROSTRUCTURE AND ELECTROMIGRATION RESISTANCE OF AL-SI-CU ALLOY ON TIN TI SUBSTRATES/

Al-Si-Cu alloy films sputter-deposited on reactively ion-sputtered TiN /Ti/SiO2 substrates were characterized and evaluated for interconnect reliability. Using x-ray diffraction techniques, both TiN and Al micro structures were analyzed and the (111) intensities of the latter corre lated with the K median time to fail (MTTF). The values of the MTTF in creased with the Al(111) intensities for the TiN/Ti/SiO2 Substrates an nealed below 400-degrees-C. A progressive decrease in both the Al(111) texture and MTTF was observed for substrates annealed above this temp erature. While the improved Al(111) texture has been attributed to an improved TiN barrier textured in the (111) crystal plane (anneals belo w 400-degrees-C), a TiO2 layer over the TiN barrier has been found res ponsible for the degradation of the Al(111) texture and the MTTF for b arrier anneals above 400-degrees-C.