YIELD Engineering Systems Inc.

Annealing is a heat treatment where the microstructure of a material is altered, causing changes in its properties such as strength and hardness. In the semiconductor industry, silicon wafers are annealed so that dopant atoms (such as boron, phosphorus or arsenic), can be incorporated into substitutional positions into the crystal lattice, which drastically changes the electrical properties of the semiconducting material.
In the case of copper, adding an anneal step:

For a YES system suited to copper annealing, visit the PBV300 product page.