Al–Cu Texture Enhancement by Underlayer Texture

Abstract

Al–Cu layered films and interconnections (Al/underlayers) were fabricated and investigated to observe the effects of underlayer texture on Al texture development and of Al texture on electromigration resistance. Al(111) texture was enhanced by controlling Ti and TiN underlayer textures. Values of full width at half maximum for Al(111) rocking curves ranged from 0.64° to 4.7° for Al–Cu films grown on Ti, TiN/Ti, and Ti/TiN/Ti underlayers. Al(111) texture and TiN(111) texture were improved when these films were consecutively deposited on Ti underlayers with (10·0) preferred orientation. Factors for Al texture development will be discussed in order to develop a model which explains texture development in terms of nucleation and growth of Al films and Al grain growth. It was confirmed that Al interconnections with strong (111) textures had long electromigration lifetimes.