Title :
Impacts of Cu Contamination on Device Reliabilities in 3-D IC Integration
Author :
Kang-Wook Lee ; Ji-Chel Bea ; Ohara, Yuki ; Murugesan, Mariappan ; Fukushima, Tetsuya ; Tanaka, T. ; Koyanagi, Mitsumasa
Author_Institution :
New Ind. Creation Hatchery Center (NICHe), Tohoku Univ., Sendai, Japan
Abstract :
The impacts of Cu contamination from a backside surface of a thinned wafer and Cu via on device reliabilities in 3-D IC integration are electrically evaluated. Intrinsic gettering (IG) layer, which was formed by high density oxygen precipitate, shows excellent Cu retardation characteristics from the backside surface of the thinned wafer. Extrinsic gettering (EG) layer, which was formed by postgrinded dry polish (DP) treatment shows good Cu retardation characteristics compared with other postgrinded treatments. The minimal 30-nm-thick Ta barrier layer in Cu via shows good barrier property to Cu diffusion from Cu via after annealing up to 60 min at 300 °C. However, it is not enough at 400 °C annealing, because the generation lifetime shows significant degradation after the initial annealing for 5 min. The DRAM cell characteristics show severe shortening retention time after an intentional Cu diffusion from the backside of the thinned DRAM chip at relatively low temperature of 300 °C.
Keywords :
DRAM chips; annealing; contamination; getters; integrated circuit reliability; precipitation; three-dimensional integrated circuits; 3D IC integration; Cu contamination; Cu diffusion; Cu retardation; DRAM cell; Ta barrier layer; annealing; backside surface; barrier property; device reliability; dry polish treatment; extrinsic gettering layer; generation lifetime; high density oxygen precipitate; intrinsic gettering layer; size 30 mm; temperature 300 degC; thinned wafer; time 60 min; Capacitance; Random access memory; 3-D LSI; Capacitance–time (C–t); Cu diffusion; dynamic random access memory (DRAM) retention characteristics; gettering layer;
Journal_Title :
Device and Materials Reliability, IEEE Transactions on
DOI :
10.1109/TDMR.2013.2258022