高深宽比硅孔溅射铜种子层工艺的探索与研究

Exploration and Research on the Technology of High Aspect Ratio Silicon Hole Sputtering Copper Seed Layer

硅通孔技术(TSV)是当前非常热门的高密度封装技术,但由于常规薄膜沉积技术很难在高深宽比的硅孔内沉积铜、钨等金属种子层,硅通孔技术中存在深硅孔金属化困难的工艺问题。通过对倾斜溅射时铜原子二维非对心碰撞前后入射角度的变化关系进行模拟计算发现,当原子碰撞有能量损失时,入射到硅孔内的铜原子角度会发生改变,有助于其沉积在硅孔深处。本文利用负偏压辅助多个铜靶共焦溅射的方式,在不同深宽比的硅盲孔中沉积铜种子层,验证了该方法的可行性,并通过三靶共焦溅射成功在深宽比8∶1的硅孔内实现了铜种子层的沉积。

Through-silicon-via is currently a very popular high-density packaging technology,but the metallization of deep silicon holes in silicon through-hole technology is a very difficult process issue,because conventional magnetron sputtering techniques are difficult to deposit seed layers such as copper and tungsten in high aspect ratio silicon holes.Through simulation and calculation of the relationship between the two-dimensional non centered collision angles of copper atoms during oblique sputtering,it was found that when there is energy loss in atomic collisions,the angle of copper atoms incident into the silicon hole changes,which helps to deposit at the depth of the silicon hole.In this paper,copper seed layers were deposited in silicon blind holes with different aspect ratios by using negative bias assisted confocal sputtering of multiple copper targets to verify the feasibility of this method,and the deposition of copper seed layers in silicon pores with a depth to width ratio of 8:1 was successfully achieved by three target co sputtering.