AVS 61st International Symposium & Exhibition
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuA

Paper PS-TuA10
Novel Fluorocarbons Chemistries to Enable 3D NAND High Aspect Ratio Etching

Tuesday, November 11, 2014, 5:20 pm, Room 308

Session: Advanced BEOL/Interconnect Etching
Presenter: Venkateswara Pallem, American Air Liquide
Authors: R. Gupta, American Air Liquide
B. Lefevre, American Air Liquide
V. Pallem, American Air Liquide
N. Stafford, American Air Liquide
J.M. Kim, Applied Materials Inc.
K. Doan, Applied Materials Inc.
S. Nemani, Applied Materials Inc.
Correspondent: Click to Email
The development of high aspect ratio etch processes is one of the challenges that must be overcome for the next generation devices such as 3D NAND. In addition to tool improvements a new variable for optimization of the process is the fluorocarbon chemistry (FC) that is used. The study presented here examines the effect of different FC on high aspect ratio etch processes. In this study several novel fluorocarbons chemistries have been tested using a 200mm dual frequency CCP etch tool. Novel chemistries are used to etch planar film of SiO2, amorphous carbon, and SiN for which etch rates are measured as well as the deposition rate on bare Si. The O2 flow rate is varied in order to find the optimum ratio of etch gas to O2. High aspect ratio structures with oxide/nitride stack are etched using optimum condition. SEM cross-sections of pattern structures were analyzed to determine chemistry effect on etch profile, selectivities and mask preservation. By varying F:C ratios and molecular structures, high aspect ratio structure (>25) were obtained with sub 100nm features with improved profile compared to standard FC chemistry. Mass spectrometry was also performed on pure etch gas. Variation of the electron energy from 10 to 100eV gives fragments concentration which can help to predict fragmentation of the molecules under plasma condition and etch performance of molecules. The most promising chemistry was tested on Applied Materials 300mm Dielectric Etch tool.