A planar interconnection technology utilizing the selective deposition of tungsten

This paper reports on the development of a planar interconnection technology based on the selective deposition of tungsten (W). The W interconnection technology (WIT) relies on the implanting of Si or W into oxide channels, which are later selectively filled with W. The process inherently yields a planar surface structure after each level of metallization so that no complex planarization techniques are required. A comprehensive study using Si and W implants for the nucleation of selective CVD W in oxide channels has been performed. The experiments demonstrate that a minimum Si concentration of 4.9 x 1021 cm-3 is required to nucleate W on the oxide, whereas a W concentration of less than 7.3 x 1020 cm-3 is needed. The interconnections exhibit a resistivity of 7 x 10-6 Ω · cm for both the Si and W implants. The adhesion of W film on oxide produced with the W implantation is superior to that produced with the Si implantation with no lifting observed on long lines