Single-Crystalline-Silicon TSV Based On Dry Filling and Oxidation of Submicron Silicon Particles

This paper introduces submicron silicon particles into through-silicon insulation, and develops an all-silicon single-crystalline-silicon (SCS) TSV for MEMS front-end process. Submicron silicon particles are filled into annular trenches on one side of low-resistance SCS wafer by a silica-gel scraper, which is followed by surface cleaning and oxidation to wipe off residual particles and to turn trench-filled incompact silicon particles into solidified SiO
2
liner respectively. After the same process is carried out on the other side, isolated silicon conductive pillars are formed and strongly anchored to substrate. The proposed SCS TSV is not limited by wafer thickness. Besides, it omits thinning step and chemical mechanical polishing (CMP) step, thus ensuring good profile quality and surface quality of this TSV wafer. Experimental results reveal that the insulation resistance value of each via reaches TΩ-level. The developed 4-inch SCS TSV wafer proves to be qualified for wafer-level bonding.