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本文利用ANSYS有限元软件分别对用TaN和ZrN作为扩散阻挡层的Cu/barrier/SiO2/Si结构中铜线的热应力分布进行仿真。研究热载荷350℃到20℃不同阻挡层材料单大马士革和双大马士革两种结构铜互连线的热应力。通过仿真结果得到:单大马士革结构中,在阻挡层材料为ZrN时铜线中等效应力(700MPa)比阻挡层材料为TaN时等效应力(800MPa)小;双大马士革结构中,用ZrN作为阻挡层铜线中各个方向的热应力σx、σy和σz分别比TaN作为阻挡层时小100MPa、300MPa和200MPa。本文还研究阻挡层材料分别为ZrN和TaN时,改变阻挡层的厚度对铜线热应力的影响。结果表明,热应力随着阻挡层厚度的增加而增加。各种厚度ZrN作为扩散阻挡层时的应力都比TaN作为扩散阻挡层的应力小,x、y和z方向的应力SX(ZrN)、SY(ZrN)和SZ(ZrN)分别减少了50MPa、200MPa和50MPa。
In this paper, ANSYS finite element software was used to simulate the thermal stress distribution of copper wire in Cu / barrier / SiO2 / Si structure with TaN and ZrN diffusion barriers. The thermal stresses of two kinds of copper interconnects with different barrier materials of single damask and double damascene at 350 ℃ to 20 ℃ were studied. The simulation results show that when the barrier material is ZrN, the equivalent stress (700MPa) in the copper wire is smaller than the equivalent stress (800MPa) when the barrier material is TaN in the single Damascene structure; and ZrN is used as the barrier in the double Damascene structure The thermal stresses σx, σy and σz in all directions in the copper wire are respectively 100 MPa, 300 MPa and 200 MPa less than those of TaN as a barrier layer. In this paper, we also study the impact of the thickness of the barrier layer on the thermal stress of copper wire when the barrier materials are ZrN and TaN respectively. The results show that the thermal stress increases with the increase of the thickness of the barrier layer. Stress at various thicknesses of ZrN as a diffusion barrier is smaller than that of TaN at a diffusion barrier, and stresses SX (ZrN), SY (ZrN) and SZ (ZrN) in the x, y and z directions are reduced by 50 MPa and 200 MPa, respectively And 50MPa.