Self-aligned three dimensional chip stack and method for making the same

Abstract

Self-aligned three dimensional vertically stacked chip stacks and processes for forming the same generally include two or more vertically stacked chips supported by a scaffolding structure, the scaffolding structure defined by a first scaffolding trench and at least one additional scaffolding trench, the first scaffolding trench comprising a bottom surface having a width and a sidewall having a height extending from the bottom surface to define a lowermost trench in a scaffolding layer, the at least one additional scaffolding trench overlaying the first scaffolding trench having a sidewall having a height and a width, wherein the width of the at least one scaffolding trench is greater than the first scaffolding trench width to define a first stair between the first scaffolding trench and the at least one additional trench; a first chip secured to the first scaffolding trench having a height less than the first scaffolding trench sidewall height; and at least one additional chip secured to and supported by the first stair, wherein the at least one additional chip is vertically spaced apart from the first chip.