|학술대회||2010년 가을 (11/11 ~ 11/12, 무주리조트)|
|발표분야||E. Advanced Materials and processing Technology(첨단재료공정기술)|
|제목||Self-forming barrier process using PEALD Cu-Mn alloy for advanced Cu interconnect|
|초록||With the scaling down of ultra large-scale integration (ULSI) to the sub-50 nm technology node, the need for an ultrathin, continuous and conformal diffusion barrier and Cu seed layer is increasing. However, diffusion barrier and Cu seed layer formation with a physical vapor deposition (PVD) method has become difficult as the technology node is reduced to 30 nm and beyond. Recent work on self-forming barrier processes using PVD Cu alloys have attracted great attention due to the capability of conformal ultrathin barrier formation using a simple technique .
In this works, conformal Cu-Mn seed layers were deposited by plasma enhanced atomic layer deposition (PEALD) at low temperature (120 °C), and the Mn content in the Cu-Mn alloys were controlled form 0 to approximately 10 atomic percent with various Mn precursor feeding times. Resistivity of the Cu-Mn alloy films decreased by annealing due to out-diffusion of Mn atoms. Out-diffused Mn atoms were segregated to the surface of the film and interface between a Cu-Mn alloy and SiO2, resulting in self-formed MnOx and MnSixOy, respectively. X-ray diffraction patterns, cross sectional transmission electron microscopy images, and leakage current of SiO2 inter metal dielectric on the samples annealed at 500 °C revealed no Cu diffusion through the barrier. The adhesion between Cu and SiO2 was enhanced by the formation of MnSixOy. The dielectric constant of MnSixOy barrier was controlled with annealing temperature. The obtained results indicated that the MnSixOy is an excellent barrier layer without negative influences on the capacitance of inter-metal dielectric. Continuous and conductive Cu-Mn seed layers were deposited with PEALD into 24 nm SiO2 trench, enabling a low temperature process, and the trench was perfectly filled using electrochemical plating (ECD) under conventional conditions. The MnSixOy barrier from PEALD Cu-Mn alloy should make it possible to extend the current electroplating process to devices with much smaller features.
|저자||문대용1, 한동석2, 박종완1|
|소속||1한양대, 2한양대하교 나노반도체공학과|
|키워드||Cu interconnect; diffusion barrier; seed layer; atomic layer deposition|