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随着集成电路向高密度小尺寸方向发展,铜互连已成为目前集成电路主要使用的互连技术,但球状缺陷的形成会影响产品的质量.本文研究了长等待时间下铜互连线中球状缺陷的形成机理,分析了其造成器件失效的原因,并提出了相应的解决方案.研究显示,前道工序应力残留致铜晶界处应变再结晶是这种形式球状缺陷形成的主要原因.球状缺陷会使两层金属之间形成额外通孔,从而引起短路或漏电,导致器件失效.最后提出了相应的解决方案,通过正交实验发现铜电镀退火温度降低50℃,氮化硅淀积速率降低1 nm/s,氮化硅的膜厚提高10 nm能够有效改善这一现象.
With the development of ICs toward high density and small size, copper interconnects have become the main interconnect technology used in integrated circuits, but the formation of spherical defects will affect the quality of the products.In this paper, The formation mechanism of spherical defects was analyzed and the causes of device failure were analyzed and corresponding solutions were put forward.The research shows that strain recrystallization at the grain boundaries caused by residual stress in the previous process is the main reason for the formation of spherical defects in this form. Spherical defects will form additional holes between the two layers of metal, causing a short circuit or leakage, resulting in failure of the device.At last, the corresponding solutions are proposed, through orthogonal experiments found that the copper plating annealing temperature is reduced by 50 ℃, silicon nitride deposition A 1 nm / s rate reduction and an increase of 10 nm in silicon nitride film thickness can effectively improve this phenomenon.