CONSTRAINED NANOSECOND LASER ANNEAL OF METAL INTERCONNECT STRUCTURES

摘要

In-situ melting and crystallization of sealed cooper wires can be performed by means of laser annealing for a duration of nanoseconds. The intensity of the laser irradiation is selected such that molten copper wets interconnect interfaces, thereby forming an interfacial bonding arrangement that increases specular scattering of electrons. Nanosecond-scale temperature quenching preserves the formed interfacial bonding. At the same time, the fast crystallization process of sealed copper interconnects results in large copper grains, typically larger than 80 nm in lateral dimensions, on average. A typical duration of the annealing process is from about 10's to about 100's of nanoseconds. There is no degradation to interlayer low-k dielectric material despite the high anneal temperature due to ultra short duration that prevents collective motion of atoms within the dielectric material.

主权项

1. A method of annealing a metal interconnect structure comprising:
providing a metal interconnect structure containing a metallic structure including copper or a copper alloy that is embedded within at least one dielectric material layer located on a substrate, wherein a bottom surface of a dielectric cap layer contacts an entire top surface of said metallic structure, and wherein each surface of said metallic structure is in physical contact with said at least one dielectric material layer, an underlying metallic structure located underneath said metallic structure, a sidewall surface of an underlying dielectric layer, or said bottom surface of said dielectric cap layer; melting a copper-containing portion of said metallic structure by a laser irradiation; and cooling said metallic structure, wherein recrystallization of said copper-containing portion of said metallic structure occurs during a cool down period after said laser irradiation.