The technology of bump connections with high-density and reliability has been developed for 3D packaging of LSI and MEMS devices. A tapered bump has high potential to the bump connections. We focus attention on the formation of the tapered bump with self-forming, simple, and high-throughput process by a photolithography and a gas deposition (GD) method. The thickness photoresist of the holes pattern, which is formed by the photolithography, is used as the mask pattern against the deposition of the Au nanoparticles in the GD method. The deposited Au nanoparticles also horizontally grow so that the shaded mask is gradually formed along edge of the holes pattern, and completely cover in the holes. The micro-cone-shaped Au bump can be automatically formed.