3D device packaging using through-substrate posts

A method for 3D device packaging utilizes through-substrate metal posts to mechanically and electrically bond two or more dice. The first die includes a set of access holes extending from a surface of the first die to a set of pads at a metal layer of the first die. The second die includes a set of metal posts. The first die and the second die are stacked such that each metal post extends from a surface of the second die toward a corresponding pad via a corresponding access hole. The first die and second die are mechanically and electrically bonded via solder joints formed between the metal posts and the corresponding pads.