Method for permanent connection of two metal surfaces
A process for the production of a permanent, electrically conductive connection between a first metal surface of a first substrate and a second metal surface of a second substrate, wherein a permanent, electrically conductive connection is produced, at least primarily, by substitution diffusion between metal ions and/or metal atoms of the two metal surfaces.
1. A process for forming a permanent, electrically conductive connection between metallic contact surfaces of a first substrate and metallic contact surfaces of a second substrate, the process comprising:
conditioning the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate to promote diffusion of metal atoms between the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate when the metallic contact surfaces of the first substrate are brought into contact with the metallic contact surfaces of the second substrate, the conditioning comprising bombarding the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate with gas ions;
aligning the metallic contact surfaces and non-metallic regions of the first substrate with the metallic contact surfaces and non-metallic regions of the second substrate, the non-metallic regions of the first substrate surrounding the metallic contact surfaces of the first substrate, the non-metallic regions of the second substrate surrounding the metallic contact surfaces of the second substrate; and
bringing the metallic contact surfaces and the non-metallic regions of the first substrate into respective contact with the metallic contact surfaces and the non-metallic regions of the second substrate; and
after the bringing into the respective contact, bonding the metallic contact surfaces of the first substrate to the metallic contact surfaces of the second substrate and the non-metallic regions of the first substrate to the non-metallic regions of the second substrate, the bonding comprising treating the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate with a process temperature that is less than 300° C. to promote diffusion of metal atoms between the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate and reorganization of the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate such that surface defects produced by the bombarding in respective layers near the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate are eliminated to form the permanent, electrically conductive connection between the metallic contact surfaces of the first substrate and the metallic contact surfaces of the second substrate.
2. The process according to claim 1 , wherein the gas ions are hydrogen ions.
3. The process according to claim 1 , wherein the metallic contact surfaces of the first substrate are brought into contact with the metallic contact surfaces of the second substrate at the same time as the non-metallic regions of the first substrate are brought into contact with the non-metallic regions of the second substrate to initiate the grain boundary diffusion.
4. The process according to claim 1 , wherein, during the conditioning, aligning, bringing into contact, and bonding, the process temperature is less than 300° C.