Control of FSG/SiO/sub 2/ interlayer conditions to prevent Al-wiring delamination caused by F accumulation at Ti/SiO/sub 2/

The optimum conditions of a fluorinated silica glass/SiO/sub 2/ (FSG/SiO/sub 2/) interlayer were investigated for preventing Al-wiring delamination. TiF/sub x/ formation by F atoms transported from the FSG film to the Ti/SiO/sub 2/ interface during the metallization process induced the delamination. Correlation between the Al-wiring delamination and F concentration at Ti/SiO/sub 2/ was demonstrated by a 3-D mapping of F concentrations at Ti/SiO/sub 2/ with various thickness of SiO/sub 2/ film and F content in the FSG film. Some treatments of the FSG/SiO/sub 2/ interlayer to reduce F accumulation at Ti/SiO/sub 2/ were also examined. It was revealed that more than 4500-/spl Aring/ thickness and strain relaxation of the compressive SiO/sub 2/ film were effective for F reduction at Ti/SiO/sub 2/. On the other hand, F concentration at Ti/SiO/sub 2/ was independent of F content in the FSG film in the range of 2-5 %. F content in FSG film should be kept as much as possible, that is, 4-5 % not to increase the capacitance between adjacent metal lines. The Al-wiring delamination was prevented by introducing these parameters of the FSG/SiO/sub 2/ interlayer into the fabrication line.