A method of forming integrated circuit device, including: providing a substrate; forming an integrated circuit region on the substrate, the integrated circuit region comprising a dielectric stack; forming a seal ring in the dielectric stack and around a periphery of the integrated circuit region; forming a trench around the seal ring and the trench exposing a sidewall of the dielectric stack; forming a moisture blocking layer continuously covering the integrated circuit region and extending to the sidewall of the dielectric stack, thereby sealing a boundary between two adjacent dielectric films in the dielectric stack; and forming a passivation layer over the moisture blocking layer.