The Effects of Metal Structure on the Junction Stability of Sub-micron Contacts Using Selective CVD-W Plug

금속 구조 변화에 따른 선택 화학기상증착 W Plug의 접합 신뢰성 연구

  • 최경근 (현대전자㈜ 반도체 연구소) ;
  • 김춘환 (현대전자㈜ 반도체 연구소) ;
  • 박흥락 (현대전자㈜ 반도체 연구소) ;
  • 고철기 (현대전자㈜ 반도체 연구소)
  • Published : 1994.05.01

Abstract

The junction failure mechanism of W plugs has not been fully understood while the selective W deposition has been widely used for plugging interconnection lines. In this paper, the thermal stability and junction failure mechanism of sub-micron contacts using selective CVD-W plugs were intensively studied with the metal lines of AISiCu, Ti/AISiCu and TiN/AISiCu. The experimental results showed that the contact chain resistance and leakage current in the AISiCu and Ti/AISiCu metallizations were significantly degraded after annealing. From the SEM analysis, it was found that the junction spiking, due to the Al atoms diffusion along the porous interface between selective CVD-W and contactside wall, caused the junction failure. In constast, there was no degradation of the contact resistance and junction leakage current in TiN/AISiCu metal structu-re. It is believed that the TiN barrier layer could prevent AI(Ti) atoms Fromdiffusing. Therefore, TiN barrier between W plug and Al should be used to impro-ve the thermal stability of sub-micron contacts using the selective CVD-W plugs.

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