Plasma Anisotropic CVD for Cu Interconnects in LSI

我们已经实现了各向异性沉积的铜，其中铜填充优先从底部的沟槽，而不是被沉积在其侧壁上，使用H-辅助等离子体化学气相沉积。各向异性沉积具有两个有趣的特征。一个是沟槽宽度越窄，其底部的沉积速率越快。另一个是自限制特性，即在沟槽中的沉积在完全填充后自动停止。这种类型的沉积具有克服与保形填充相关的常见问题的潜力：小于沟槽宽度一半的小晶粒尺寸，以及形成具有相对高浓度的残余杂质的接缝。

We have realized anisotropic deposition of Cu, for which Cu is filled preferentially from the bottom of trenches without being deposited on their sidewall, using H-assisted plasma chemical vapor deposition. The anisotropic deposition has two interesting features. One is the fact that the narrower the width of trench is, the faster the deposition rate on its bottom becomes. The other is the self-limiting characteristic that the deposition in the trench stops automatically just after filling completely it. Such type of deposition has a potential to overcome common problems associated with conformal filling : a small crystal grain size below a half of the trench width, and formation of a seam with residual impurities of relatively high concentration.