Microstructural Modification of Thick Copper Films to Optimize Chemical-Mechanical Planarization of Through-Wafer Interconnects

Patrick Andersen, Mariela Bentancur, Megan Frary

Research output: Contribution to conferencePresentation

Abstract

Large through-wafer interconnects may be required for high current applications or novel devices like backside connected solar cells. The electroplated copper film required to fill large vias is typically much thicker than conventional films and has a much different microstructure. Previous work has shown films with smaller, more equiaxed grains tend to have lower removal rates and different topography after chemical mechanical planarization (CMP). Here we alter the plating parameters (bath chemistry and current density) and thermal treatments in order to create different microstructures and measure their effects on CMP outputs. Electron backscatter diffraction is used to quantify microstructural parameters such as grain size and crystallographic texture. We find that annealing thick copper films after complete room-temperature relaxation has a significant impact on CMP outputs such as removal rate and surface roughness. The results of this work could be applied to optimize CMP of thick copper films and through-wafer interconnects.

Original languageAmerican English
StatePublished - 11 Mar 2008
Event2008 TMS Annual Meeting -
Duration: 11 Mar 2008 → …

Conference

Conference2008 TMS Annual Meeting
Period11/03/08 → …

EGS Disciplines

  • Materials Science and Engineering

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