IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Thursday Sessions
       Session PS-ThP

Paper PS-ThP24
Resist Trimming Process Using High Density Plasma for Sub-0.1µm MOSFET

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Plasma Etching Poster Session
Presenter: C.Y. Sin, National University of Singapore
Authors: C.Y. Sin, National University of Singapore
B.H. Chen, National University of Singapore
K. Loh, Chartered Semiconductor Manufacturing, Singapore
P. Yelehanka, Chartered Semiconductor Manufacturing, Singapore
Correspondent: Click to Email
Because of the resolution limit of the 248nm lithography and immaturity of the 193nm lithography process, resist trimming process using oxygen containing gas mixture has been developed for sub-0.1@micro@m MOSFET fabrication. In this paper, the characteristics of resists trimming in high-density plasma were investigated. Experimental results are presented to show the trimming behavior of resist as a function of RF source power, bias power, temperature, linewidth to space ratio, gas composition and reactor pressure. Effect of gas composition on trimming process were evaluated using three different gas mixtures: HBr/O@sub 2@ and Cl@sub 2@/O@sub 2@ as well as CF@sub 4@/O@sub 2@. The gas mixture of CF@sub 4@/O@sub 2@ gives high trim, improved resist sidewall roughness and good uniformity. Studies of X-ray photoelectron spectroscopy (XPS) will be performed to determine the chemical composition of the resist sidewall passivation. The features studied comprised of alternate polysilicon lines and spaces. The amount trimmed is linearly proportional to trim time. For resist trimming, the experimental results revealed that the trimming process is of very feature density dependence. rim rate is dependent on linewidth to space ratio, but is independent of initial linewidth for the same linewidth to space ratio. Trim rate increases at low CF@sub 4@ gas flow ratio and then decreases. Trim rate of 0.66@micro@m/min can be achieved. The activation energies of trimming for dense and isolated line are found to be 0.13eV and 0.128eV, respectively, at gas composition of 100sccm CF@sub 4@/30sccm O@sub 2@ but have quite different pre-exponential constants, which suggests to be feature density dependence. Bias power has no significant effect on trim rate. Reactor pressure in the range from 5mTorr to 20mTorr also does not affect much the trim rate. The resist trimming process is found to be reproducible and controllable, making it a useful process for nanometer-scale device fabrication.