AVS 53rd International Symposium
    Manufacturing Science and Technology Tuesday Sessions
       Session MS-TuA

Paper MS-TuA9
Innovative Studies for Ultra High Aspect Ratio Deep Trench Etch

Tuesday, November 14, 2006, 4:40 pm, Room 2018

Session: Process Integration and Modeling for Nano-scale Semiconductor Devices
Presenter: S. Pamarthy, Applied Materials
Authors: S. Pamarthy, Applied Materials
F. Ameri, Applied Materials
D. Gutierrez, Applied Materials
D. Scanlan, Applied Materials
F. Schaeftlein, Applied Materials
Correspondent: Click to Email
A key challenge that DRAM manufacturers are facing today is achieving very high aspect ratios in deep trench etch. Future DRAM technology shrinks require development of hardware and process solutions to etch deep trench features at aspect ratios >80:1, for which there is no known available solution today. This paper describes how this key technical challenge can be overcome to implement a manufacturing solution to meet the aspect ratio requirements for DRAM DT technology needs of 65nm and beyond. The entire development path is traced, from initial plasma generation and gas flow modeling studies, early concept experiments involving plasma characterization, and process condition explorations and eventually to a final reactor design, including the innovation of multiple uniformity tuning knobs. The paper also focuses on studies done with each of the following hardware/process tests: Gas Flow Ratio Control (FRC), Dual Zone Coolant Ceramic ESC and Independent Gas Injection (IGI) independently and the impact these tests have on some critical aspects of deep trench etch such as center to edge trench depth non-uniformity, center to edge bottom CD uniformity, mask selectivity, Top CD widening, and mask remaining uniformity across the wafer. The study shows that some of the limitations of the current production chambers can be improved with these potential features. The paper also talks about how a future reactor can potentially be the only chamber of its kind with a clear capability to tune the capacitance of each DRAM cell across the wafer using these innovative features. For selectivity improvements, studies with new silicon source gases such as SiF4 and SiCl4 as additional sources for re-deposition during the etch process are discussed.