US Patent 9941153 Pad structure and manufacturing method thereof

A pad structure including a plurality of material pairs and a plurality of pads is provided. The material pairs are stacked on a substrate to form a stair step structure. A stair step of the stair step structure includes one of material pairs. Each of the material pairs includes a conductive layer and a dielectric layer on the conductive layer. Each of the pads is embedded in one stair step of the stair step structure and exposed by the dielectric layer corresponding to the one stair step and another stair step above the one stair step. A thickness of one of the pads is greater than a thickness of one of the conductive layers.