Patent ID: 9027821
Filing Date: 2015-05-12
Classification: H01L

Abstract:
1. A process of assembly by direct bonding of a first and of a second element, the first element having a first surface including first copper portions separated by at least one first dielectric material, and the second element having a second surface including second copper portions separated by at least one second dielectric material, the process comprising: a) polishing the first surface and the second surface, such that the first and the second surfaces that are to be assembled are compatible with assembly by bonding, in terms of roughness and hydrophilicity; b) forming a first diffusion barrier selectively on the first copper portions of the first element and a second diffusion barrier selectively on the second copper portions of the second element, such that a surface of the first diffusion barrier is level with the first surface of the first element, and a surface of the second diffusion barrier is level with the second surface of the second element, each to within less than 5 nanometers, the first diffusion barrier and the second diffusion barrier being a cobalt or nickel alloy; and c) bringing the first surface of the first element into contact with the second surface of the second element, such that the first and second copper portions at least partly cover each other, forming overlapping areas, and such that direct bonding is obtained between the at least one first dielectric material and the at least one second dielectric material, and along the overlapping areas of the first and the second copper portions.