A 0.25 mu m via plug process using selective CVD aluminium for multilevel interconnection

A multilevel interconnection with 0.25- mu m via holes has been successfully fabricated using a selective CVD (chemical vapor deposition) aluminum via plug process. Via holes on first-level aluminum interconnections have been fully plugged for the first time by selective CVD aluminum in combination with in situ RF cleaning. Specific contact resistivities of CVD aluminum via plugs are estimated to be as low as 5*10/sup -10/ Omega cm/sup 2/, and the yield for 10/sup 4/ via chains is 100% for test patterns with various via diameters of 0.25-2 mu m. Electromigration tests for the CVD aluminum plugs demonstrate extremely high reliability compared to conventional sputtering samples. The results presented demonstrate that the selective aluminum CVD process is a promising technique for future quarter-micron LSIs.<
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