AVS 58th Annual International Symposium and Exhibition
    Nanomanufacturing Science and Technology Focus Topic Tuesday Sessions
       Session NM+MN+MS+TF-TuM

Paper NM+MN+MS+TF-TuM9
Measured Backscattered Electron Profile for Optimized Proximity Effect Correction

Tuesday, November 1, 2011, 10:40 am, Room 207

Session: Lithography Strategies for Nanomanufacturing
Presenter: David Czaplewski, Argonne National Laboratory
Authors: D.A. Czaplewski, Argonne National Laboratory
L.E. Ocola, Argonne National Laboratory
Correspondent: Click to Email
Electron beam (e-beam) lithography has been used to create nanoscale patterns in myriad of resists with features as small as single nanometers. When creating resist features on the single nanometer length scale, the process window to create the desire resist structure becomes increasingly small. Overdosing or under dosing of critical features causes changes in critical dimensions. In addition to the dose required for a single feature, the contribution of additional dose due to proximity of nearby features must be considered. To solve this problem, finite element analysis software packages are available for adjusting dose assignments for different features based on size, shape, and placement with respect to other features. The FEM software can only work as good as the input parameters. These parameters come from the backscattered electron profile. Here, we present the measured electron backscattered profile using a negative e-beam resist. In order to measure the backscattered profile, we use a pattern of intersecting lines surrounded by a large annulus. The lines are measured while the annulus provides a circularly symmetric backscattered electron dose. The lines and annuli are written with varying doses. By measuring the thickness of the resist, the contribution from both the lines and the annulus can be determined for different doses and different shapes by using the resist contrast curve. By using the contrast curve to assign doses to specific resist thicknesses, the specific resist and developer effects are removed from the data. The resultant backscattered electron profile can be used as input into the FEM model to create more accurate resist dose assignments for proximity effect corrected patterns for all resists.