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:
- Improves properties of the copper layer
- Increases grain size for faster polishing
- Provides better conductivity
- Reduces surface tension
- Minimizes electromigration
- Allows a consistent CMP rate across the wafer
For a YES system suited to copper annealing, visit the YES-VertaCure page.