Wetting behavior of polymer liquid in insulation process for through silicon via

3D packaging using through silicon via (TSV) technology is becoming important in the integrated circuit (IC) packaging industry. This paper reports the wetting behavior of polymer liquids in the insulation deposition process by spin coating. Two methods containing adding wetting agent into polymer liquid and coupling agent treatments to wafer surface were implemented to improve the wettability between the liquid and the wafer. From the viscosity tests, it was found that the wetting agent could improve the flowability and have little effect on the thixotropy of liquid. Besides, the surface tension of liquid was shifted to 31.14 mN/m from 32.16 mN/m with the addition of wetting agent. The coupling agent treatment to sidewall of vias (silicon) could increase the adhesion work value by at least 8 mN/m and avoid the sagging. Moreover, the wetting dynamics revealed that adding wetting agent to polymer liquid and coupling agent treatments to wafer could improve the wetting rate and decrease the balanced contact angle.