AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS2-MoM

Paper PS2-MoM1
Challenges Facing Deep Trench Silicon Etching for Present and Future Trench Technology Nodes

Monday, November 15, 2004, 8:20 am, Room 213B

Session: Silicon Etching
Presenter: A.M. Paterson, Applied Materials, Inc.
Authors: A.M. Paterson, Applied Materials, Inc.
S. Pamarthy, Applied Materials, Inc.
A. Khan, Applied Materials, Inc.
F. Ameri, Applied Materials, Inc.
J.Y. Chen, Applied Materials, Inc.
H. Mohiuddin, Applied Materials, Inc.
T. Panagopoulos, Applied Materials, Inc.
J.P. Holland, Applied Materials, Inc.
T. Lill, Applied Materials, Inc.
A. Steinbach, Infineon Technologies
S. Wege, Infineon Technologies
Correspondent: Click to Email
The reduction in trench technology nodes to 90nm and beyond brings new challenges to deep trench silicon etching of capacitor structures for DRAM applications. At present gate feature sizes of 110nm requires silicon trench etching depths of 8um, with a top critical dimension of 160nm, corresponding to an aspect ratio of 50:1. The depth, and hence aspect ratio of the trench, is determined by customer capacitor cell and leakage current requirements. In the next five years, the trench nodes will reduce further to 90nm, 70nm and 65nm with the aspect ratios of the silicon trench increasing to 65:1, 80:1 and 100:1, respectively. The shrinking of the node to smaller sizes brings new challenges to semiconductor OEMS. The technology that was used for etching trenches at one node size may not give the required trench at the smaller node size. This was found to be the case when moving from 0.35µm to 0.25µm node size where the tool of choice, AMAT DPS@super TM@ DT, had limitations in obtaining the required customer specifications for the new node. After subsequent research and development at Applied Materials, a new High Aspect Ratio Trench (HART@super TM@) chamber has shown the capability of etching trenches down to the 70nm node. This paper will discuss why the choice of plasma source, source rf frequency, bias rf frequency and chamber geometry are of critical importance in achieving such high aspect ratio trenches.