Publications (2)0 Total impact

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    ABSTRACT: We report on recent experimental studies performed as part of a 3D integrated circuit (3DIC) production-worthy process module roadmap check for 300 mm wafer-to-wafer (WtW) copper-to-copper thermocompression bonding and face-to-face (F2F) aligning. Specifically, we demonstrate submicron alignment capabilities (3sigma alignment variability ~ 1 μm) post Cu bonding on topography M1V1-to-M2 Cu wafers with no interfacial voids observed and complete Cu interdiffusion, as supported by transmission electron microscopy (TEM) and electron back scatter diffraction (EBSD) data. Also, less than 0.1% clustered voids bonding uniformity were observed on bonded blanket Cu wafers. In addition to bonding quality characterization studies involving scanning acoustic microscopy (SAM) and confocal infra-red (IR) laser scanning microscopy, we report on the development of a prototype integrated IR, highspeed focused-ion-beam (FIB) technique with CAD overlay capabilities that enable the creation of site specific cross-sections and TEM samples to better observe bonding structures of interest.
    Interconnect Technology Conference (IITC), 2010 International; 07/2010
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    ABSTRACT: We report recent advances in tool and process hardening of a first of its kind 300 mm wafer-to-wafer (WtW) preprocessing, aligning, and bonding integrated tool. We have demonstrated sub-500 nm post-bond alignment accuracies for 300 mm WtW face-to-face (FtF) Cu-Cu thermocompression bonds, WtW FtF Si-Si fusion bonds, and WtW FtF oxideoxide fusion bonds. All process of record (POR) recipes that were developed had undetectable voids based on scanning acoustic microscope (C-SAM) measurements on representative bonded Cu, oxide, and Si blanket wafers. Optimized bonded patterned wafer splits in the Cu-Cu WtW thermocompression bonding step have shown alignment accuracies down to ~190 nm, the highest accuracy to date. Using an infrared-enabled, high speed focused ion beam (FIB) system (with XeF2) with a CAD overlay function to assist in selective sample preparation, we have verified that the bonding interfaces at the via chain structures with 1-5 μm diameter vias show no interfacial voids. Also, there is evidence of Cu interdiffusion, as supported by transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD) data.
    IEEE International Conference on 3D System Integration, 3DIC 2010, Munich, Germany, 16-18 November 2010; 01/2010