| 摘要 |
In the normal fabrication of copper interconnects process, after electro copper deposition (ECD), small copper grains are formed on the surface of copper and the initial grain growth of copper grain is not stable enough and it will grow up in the subsequent unavoidable thermal treatments. Currently, long time low temperature thermal process by furnace is usually adopted to produce a better initial grain growth after electro copper deposition (ECD). However, this long time low temperature thermal process is usually not good enough to stabilize the copper grain in dual damascene structure. In this invention, a fabrication process by adding an extra thermal treatment of short time high temperature processes is used to saturate copper grain growth in copper via holes. By doing this extra thermal step, the internal stress of copper becomes stable than the stress of that after the long time low temperature thermal treatment. The internal structure of copper will thus attain a more stable stress. The copper via distortion and crack phenomena can be reduced to a minimum possibility of occurrence.
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