Laser anneal of buried metallic interconnects including through silicon vias

摘要

Disclosed is a process of annealing through silicon vias (TSVs) or other deeply buried metallic interconnects using a back side laser annealing process. The process provides several advantages including sufficient grain growth and strain relief of the metal such that subsequent thermal processes do not cause further grain growth; shorter anneal times thereby reducing cycle time of 3D device fabrication; and reduced pattern sensitivity of laser absorption.

主权项

1. An apparatus for laser annealing deep metallic interconnects, comprising:
a first laser with a first wavelength and a first coupling device, and a second laser with a second wavelength, shorter than the first wavelength, and a second coupling device, wherein the first coupling device couples laser radiation from the first laser to the back side of a target structure to be laser annealed and the second coupling device couples the second laser radiation from the second laser to the front side of the target structure to be laser annealed; wherein the target structure contains, from back to front, a transparent material substrate which forms the back side of the structure, a semiconductor device region located in front of the transparent material substrate opposite to the back side of the structure, a metallic interconnect located within the transparent material substrate and semiconductor device region forming a vertical electrical connection (via), and optional back end of line (BEOL) or middle of line (MOL) component region located in front of the transparent material substrate, and wherein the second laser radiation creates an absorbing material region and the first laser radiation couples into the created absorbing material and heats it to an annealing temperature sufficient to anneal the metallic interconnect present therein.