AVS 47th International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS-FrM

Paper PS-FrM7
Hardmask Characterization for Polysilicon Gate Patterning

Friday, October 6, 2000, 10:20 am, Room 310

Session: Dielectrics II
Presenter: F.G. Celii, Texas Instruments, Inc.
Authors: F.G. Celii, Texas Instruments, Inc.
C. Gross, Texas Instruments, Inc.
S. Detweiler, Texas Instruments, Inc.
B. Trentmann, Texas Instruments, Inc.
K. Kim, Texas Instruments, Inc.
W.D. Kim, Texas Instruments, Inc.
H.-Y. Liu, Texas Instruments, Inc.
R.T. Laaksonen, Texas Instruments, Inc.
Correspondent: Click to Email
To pattern sub-0.10 µm structures required for next-generation poly-Si gates, advanced etch techniques must complement current lithography methods. One approach uses photoresist line-narrowing combined with an etch hardmask. The hardmask suitability is determined by the poly-Si etch resistance, the optical properties (if used as an anti-reflection coating (ARC) layer) and integration issues (e.g., cleanup and cost). We report the characterization of silicon-rich nitride (SRN) and silicon oxynitride (SiON) films used in poly-Si gate patterning. SiON and SRN films were deposited by PECVD in commercial 200 mm reactors. Film composition was measured by RBS and HFS spectroscopies. Typical SiON films contained ~40% Si and O, with ~20% H. Blanket films of 200 3000 Åthickness were characterized optically by FT-IR spectroscopy over 400 - 4000 cm@super -1@ and variable-angle spectroscopic ellipsometry (VASE), over 190 - 1000 nm. The VASE data provides optical constants at lithography wavelengths (193, 248 nm) of the various film compositions. We characterized patterned films by CD swing curves, in which in-line pre-etch critical dimension (CD) measurements are plotted vs. the photoresist (PR) thickness. Reflectivity minima below 1% were calculated using determined optical constants for PR/SiON/Si with SiON thicknesses at 325 Å and ~1000 Å. Etch properties and patterned profiles will also be summarized.