Paper MN-TuP2
The Study of Convex Corner Compensation for Dry Anisotropic Etching of Single Crystal Silicon in ICP-RIE

Tuesday, October 29, 2013, 6:00 pm, Room Hall B

In this paper, the compensation structure assisted the convex corner structures etch in inductively coupled plasma reactive ion etch (ICP-RIE) have been studied. The convex corner structures are widely used in many applications like micro optical devices or micro sensors. There are many researches to discuss the convex corner structure under wet etch, but rare researches for dry ICP-RIE etching. In anisotropic silicon etching, under the Bosch patent, sequentially alternating etch and passivation cycles can easily achieve high aspect ratio silicon structures. The feature size of the convex corner structures is difficult to maintain as original design at the bottom position in deep etch, due to some non-vertical movement plasma. The non-vertical movement plasma caused by collision between plasma ions, pollutants or rebounded from the etching mask. The compensation structure is design in front of the convex corner structure. The compensation structures can obstruct the non-vertical plasma to etch the convex corner structure and reduce the etch lag effect during the etch process leading to better profile at deep etch. The current study systematically investigates plasma condition to verify feasibility of the proposed method, and discusses effect of the gap between compensation structure and convex corner structure at three different gaps of 15, 10, 5µm. It demonstrate the convex corner structure have better profile with compensation structure at 5µm gap than other at deep ICP-RIE etching.

Keywords: Convex corner compensation, Inductively-Coupled-Plasma Reactive-Ion-Etch (ICP-RIE), High-aspect-ratio structure