AVS 50th International Symposium
    Nanometer Structures Tuesday Sessions
       Session NS-TuP

Paper NS-TuP20
Electroless Metal Discharge Layers for Electron Beam Lithography

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: S.L. Brandow, Naval Research Laboratory
Authors: S.L. Brandow, Naval Research Laboratory
M.-S. Chen, Naval Research Laboratory
W.J. Dressick, Naval Research Laboratory
R. Bass, Naval Research Laboratory
E. Dobisz, Hitachi Global Storage Technologies
Correspondent: Click to Email
Substrate charging during e-beam lithography on non-conductive materials can lead to severe problems in pattern placement accuracy and critical dimension (CD) error. Current methods of controlling charge include the use of conducting polymers or evaporated metal films as charge dissipation layers. We report an alternative approach utilizing ultrathin (i.e., 15-30 nm) Cu films deposited by electroless metal deposition. Our method involves the sequential chemisorption of an aminosiloxane film to the substrate of interest, binding of a colloidal Pd/Sn electroless catalyst, and brief immersion in an electroless Cu bath to deposit the ultrathin Cu film. This ligand based approach permits sufficient control of Cu thickness and uniformity to satisfy electrical conductivity, adhesion, and transparency constraints required for discharge layers. The deposition process is performed under ambient, aqueous conditions which are track-line compatible and thus should have cost advantages over conventional CVD based metallization processes. The grounded Cu film, deployed here as a resist underlayer, eliminates the 0.1 - 0.4 micron subfield stitching errors normally observed in the absence of the Cu film during resist patterning on a glass or insulating substrate. The Cu is readily removed using a nitric acid wet etch following patterning.