| AVS 55th International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS2-WeM |
| Session: | Plasma Sources |
| Presenter: | M. Block, Lam Research |
| Authors: | G.M. Amico, Lam Research M. Block, Lam Research S. Sirard, Lam Research J. Guha, Lam Research A. Leming, Lam Research A. Marakhtanov, Lam Research E.A. Hudson, Lam Research M. Srinivasan, Lam Research |
| Correspondent: | Click to Email |
At the 32nm node and below, etch rate and CD uniformity requirements for multi-layer low k dual damascene integration schemes continue to tighten. Additionally, more focus is being placed on the process uniformity at the outer 5mm of the wafer. This paper examines the effect of electrode gap and the distribution of gas injection in a capacitively coupled reactor with confined plasma and adjustable gap. Radial etch rate and CD uniformity were studied for different films, with emphasis on multi-layer DD integration schemes. Mechanisms for the influence of electrode gap on process uniformity are different for ion limited and neutral limited etch regimes. Oxide etch rate radial uniformity as a function of gap shows a correlation to ion flux measurements. Narrower gaps tend to increase edge etch rates for all films, but the gap for optimal uniformity is dependent upon film composition. For multi-layer processing, the overall uniformity can be improved by employing different gap settings for each process step.