Novel photodefined polymer-clad through-silicon via technology integrated with endpoint detection using optical emission spectroscopy

Silicon interposers with through-silicon vias (TSVs) have been widely explored to obtain high density and high bandwidth communication between chips. To reduce TSV electrical loss and stress, novel photodefined polymer-clad TSVs are fabricated. Moreover, to reduce via under or over etching during TSV fabrication and accurately predict the endpoint for TSV etching, a hybrid partial least squares-support vector machine (PLS-SVM) model of optical emission spectroscopy (OES) data is successfully demonstrated. Accurate endpoint detection results are shown for 80 μm diameter TSVs.