|학술대회||2012년 가을 (11/07 ~ 11/09, 라카이샌드파인 리조트)|
|발표분야||A. 전자/반도체 재료(Electronic and Semiconductor Materials)|
|제목||The self-forming barrier characteristics of Cu-V and Cu-Mn films for Cu interconnects|
|초록||Cu-based interconnects continue to be used in leading edge integrated circuits because of their low resistivity and improved electromigration resistance. A typical Cu metallization consists of a Cu seed layer physical vapor deposited on a PVD Ta/TaN barrier, followed by electroplating Cu. However, in this type is more difficult to form a continuous Cu seed layer with aggressive device shrinkage, resulting in void formation in the Cu interconnects.
In order to overcome this difficulty, adding small amounts of alloying elements to Cu has been suggested for the diffusion barrier characteristics, adhesion, electromigration and resistivity. It has been reported that alloying with a strong oxide former, such as Mg or Al, can improve the adhesion of copper. Besides, after heat treatment, a thin oxide layer was formed on the film surface and acted as a self-passivation layer.
In this present work, we report a Cu-V alloy as a new material as well as a Cu-Mn alloy for the self-forming barrier process. And we investigated the influence of annealing on the diffusion barrier property in a Mn-based and V-based barrier layer. The samples were annealed at various temperatures for 1 h in vacuum. X-ray diffraction revealed Cu (111), Cu (200) and Cu (220) peaks for the Cu-Mn and Cu-V alloys. Transmission electron microscopy showed that a 4–7 nm V-based interlayer self-formed and a 2–5 nm Mn-based interlayer self-formed at the interface after annealing. The resistivity of the annealed Cu-V alloy was reduced to 8.1 μΩ-cm, which is greater than the resistivity of the annealed Cu-Mn alloy. The Mn-based interlayer and V-based interlayer showed excellent thermal stability. The results show that Mn and V based Cu alloys are suitable seed layer materials for Cu interconnects.
|저자||박재형, 문대용, 한동석, 강유진, 이상호, 신소라, 박종완|
|키워드||Copper interconnect; Self-forming barrier; Vanadium; Manganese|