AVS 50th International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoM

Paper PS-MoM10
Surface and Reactor Dynamics Governing Photoresist Trim and Organic BARC Open Plasma Processing

Monday, November 3, 2003, 11:20 am, Room 315

Session: Critical Dimension Etching
Presenter: D.J. Cooperberg, Lam Research Corporation
Authors: D.J. Cooperberg, Lam Research Corporation
S. Johnston, IBM Microelectronics
D. Horak, IBM Microelectronics
V. Vahedi, Lam Research Corporation
Correspondent: Click to Email
Photoresist trimming is employed to obtain acceptable feature profiles in sub-130nm linewidths. For logic applications, the process offers a means of shrinking gate length to values that are smaller than can be printed directly with a chosen lithographic technology. When organic bottom anti-reflective coatings (O-BARC) are used to assist photolithography the photoresist trimming can be performed before, during, or after an in-situ O-BARC opening process. The trimmed PR and opened O-BARC are used as a mask for either a hardmask open or a gate etch process. In this talk we will present process trends for O@sub 2@/CF@sub 4@/N@sub 2@ photoresist trim and O-BARC open plasma processing. We have measured the effect of several reactor settings as well as wafer topology on vertical and trim (lateral) etch rates. Reactor settings studied include inductively coupled power, bias power, gas mixture, and electrode temperature. In addition, the effects of variations in exposed area, local pattern density, and microloading or aspect ratio have been studied. It will be shown that local pattern density gradients over a length scale @>=@ the gas mean free path can effect etch uniformity. Trim rates are measured during the O-BARC open process and the trim process separately. It will be shown that the dependence of trim rate on aspect ratio changes dramatically during these two steps. Our experiments are used to identify the appropriate semi-empirical models for the surface kinetics and intra-feature transport which govern feature scale profile evolution. Additionally our experiments can be used to partially characterize reactor dynamics and the transport of the primary etchant, O atoms.