Atomic force microscopy study of shape evolution of Cu micropatterns.

P.C DOS SANTOS CLARO; P. L. SCHILARDI; GA BENITEZ,; B. BLUM; R. C. SALVAREZZA

Mar del Plata

Simposio; 4th Latin American Symposium on Scanning Probe Microscopy, IV LASPM; 2007

<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:1; mso-generic-font-family:roman; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:0 0 0 0 0 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Arial","sans-serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Thin films are usually deposited on surfaces using techniques based on atomic or molecular scale physics and chemistry. Physical vapor deposition (PVD) of thin films relies on the removal of atoms from a solid or a liquid by energetic means and the subsequent deposition of those atoms on a nearby surface by following ballistic trajectories [1]. Frequently, masks on or just above the surfaces are used to select deposition areas for building complex architectures. Evaporation through masks either in well defined proximity or in contact with the surface, normally allows a controlled amount of material to be deposited only and exactly at the locations where it is needed, thereby avoiding further processing. We have investigated the growth of Cu micropatterns by masked PVD on rigid polymer, organic film-coated Au, and glass substrates. We found that two concurrent processes take place at different rates: direct incorporation at the exposed regions, with a high velocity, and slow growth at the shadowed regions. Depending on the deposition time t, we can tune from quasi 2D isolated metal patterns, to a complete 3D patterned metallic film on the foreign substrate (Fig.1a-d). Analysis of pattern evolution through AFM imaging, shows that direct incorporation at the top of the exposed areas, combined with lateral growth at the base of the patterns towards the shadowed regions, determine the final structure of the deposit. Lateral growth at top of the patterns is not significant for the time periods explored in the present work and the shape of the pattern is preserved during deposition. Our results indicate that it is possible to control the shape and height of the depositing material on the substrate. Moreover, experiments show that a transparent-opaque transition is present at intermediate/long deposition times.