Semiconductor device and method of making bumpless flipchip interconnect structures

Abstract

A semiconductor device includes a substrate with contact pads. A mask is disposed over the substrate. Aluminum-wettable conductive paste is printed over the contact pads of the substrate. A semiconductor die is disposed over the aluminum-wettable conductive paste. The aluminum-wettable conductive paste is reflowed to form an interconnect structure over the contact pads of the substrate. The contact pads include aluminum. Contact pads of the semiconductor die are disposed over the aluminum-wettable conductive paste. The aluminum-wettable conductive paste is reflowed to form an interconnect structure between the contact pads of the semiconductor die and the contact pads of the substrate. The interconnect structure is formed directly on the contact pads of the substrate and semiconductor die. The contact pads of the semiconductor die are etched prior to reflowing the aluminum-wettable conductive paste. An epoxy pre-dot to maintain a separation between the semiconductor die and substrate.