Flip chip interconnection with etched posts on a microelectronic element joined to etched posts on a substrate by a fusible metal and corresponding manufacturing method

摘要

A packaged microelectronic assembly includes a microelectronic element (104) joined to a substrate (102, 402). The microelectronic element (104) has a front surface (122) and a plurality of first solid metal posts (110) extending away from the front surface (122). Each of the first posts (110) has a width (W2) in a direction of the front surface (122) and a height (H2) extending from the front surface (122), wherein the height (H2) is at least half of the width (W2). The substrate (102, 402) has a top surface (101, 401) and a plurality of second solid metal posts (108) extending from the top surface (101, 401) and joined to the first solid metal posts (110) by a fusible metal (130), each second post (108) having a second width (W1) in a direction along the top surface (101, 401) and each projecting to a second height (H1) above the top surface (101, 401). The substrate (402) also has conductive interconnects (407) extending through the substrate (402) and electrically connecting terminals at a bottom surface (403) opposite the top surface (401) with the second solid metal posts (108). The plurality of first solid metal posts (110) and the plurality of second solid metal posts (108) are etched metal posts. The posts (110, 108) may have a frustoconical shape defined by the etching process.