Low cost TSV fabrication technologies using anisotropic Si wet etching and conformal electroless plating of barrier and seed metals

We developed TSV fabrication process using the anisotropic wet etching of Si assisted by noble metal catalyst and electroless plating of CoWB barrier and Cu seed layers. These methods are essentially low cost as compared to conventional dry etching and CVD methods which use high vacuum chamber systems. Controllability of anisotropic Si etching is improved with the use of catalytic Au disk with nanopores and adequate choice of a mixing ratio of HF and H2O2 in etching solutions. Conformal deposition of CoWB barrier film is possible even for a high aspect ratio TSV with choice of adequate temperature. We have developed equipment of 8 inch processes for both Si etching and electroless plating.