A Novel Liner Formation Strategy for Double-sided Through-silicon-via (TSV) Process

In this paper, a novel polyimide (PI) liner formation strategy is proposed for double-sided through-silicon-via (TSV) process. Combined with the front-side PI deposition by the vacuum-assisted spin-coating technique, the back-side thinning and chemical mechanical polishing (CMP), and the back-side PI deposition through an optimized spin-coating process, continuous PI layer is successfully formed on both sides of the substrate surface as well as the sidewall of TSVs with diameter of 40 μm and height of 210 μm. Besides, the impacts of the key spin-coating parameters such as PI viscosity and spinning speed are investigated to optimize the formation of the back-side PI insulation layer. The proposed liner formation strategy enables the double-sided TSV process with PI liner, which features low complexity and high reliability.