Application of high-pressure annealing process to dual damascene copper interconnections : Special issue on materials-related issues for Cu interconnects used in ultra high speed large scaled integrated Si devices

We have carried out a detailed study of the relevant process techniques by using high-pressure annealing in order to embed Cu interconnections flawlessly into via holes or trenches, and have thereby identified a process technique increase the reliability of electrical circuits. In the present study, Cu interconnections were subjected to heat treatment in a high-pressure argon gas atmosphere (150 MPa) with the prospect that such a process might lead to optimized conditions for creating the embedded Cu interconnection by preventing the occurrence of minute voids, improving the distribution of poly-crystalline orientation and improving the adhesive strength between Cu and TaN (barrier layers), thereby increasing the reliability of Cu interconnections and consequently improve the yield. This paper describes the effects of the high-pressure annealing process for dual damascene Cu interconnections in some detail.