| abstract |
A packaged microelectronic element (900) can include a microelectronic element (902) having a front surface (909) and a plurality of first solid metal posts (916) extending away from the front surface. A substrate (901) can have a major surface (906) and a plurality of conductive elements (912) exposed at the major surface and joined to the first solid metal posts (916). In particular examples, the conductive elements (912) can be bond pads (992) or can be second posts (108) having top surfaces (111) and edge surfaces (113) extending at substantial angles away therefrom. Each first solid metal post (916) can include a base region (36) adjacent to the microelectronic element (902) and a tip region (32) remote from the microelectronic element, the base region and tip region having respective concave circumferential surfaces (46, 44). The first solid metal posts (916) are formed in a multi-step etching process which allows formation of unitary metallic microcontacts or posts from a single metallic layer with combinations of pitch, tip diameter and height not attainable in conventional etching processes. As a variation, posts (932) extending from a top surface of the substrate (921) include multiple - etched conductive posts while posts (936) extending from the microelectronic element (922) may be any type of conductive posts or, as another variation, posts (952) extending from a top surface of the substrate (941) and posts (956) extending from a front surface of the microelectronic element (942) include multiple - etched conductive posts. |