Fluidic self-assembly may be utilized to form a stack of two integrated circuits. The integrated circuits may include surface mount electrical connections and surface features that control the alignment between the integrated circuits. In particular, the contacts may be provided on one side of each integrated circuit and surface features may cause the integrated circuits to align with one another in an immersion fluid. The aligned circuits may join to form physical and electrical connections. The resulting structure may be a stack of two integrated circuits electrically coupled to one another.