Copper Wires for High Speed Logic LSI Prepared by Low Pressure Long Throw Sputtering Method

Abstract

Copper sputtering method for fabrication of high performance logic LSI was studied. Extension of target to substrate distance is effective to improve step coverage of sputtered film combined with reduced operation pressure.Step coverage of low pressure long throw sputtering method also strongly depends upon the feature size of trenches and holes which are formed on silicon wafer. Sub-micron holes and trenches are successfully filled with copper by using this sputtering process followed by re-flow annealing process. Hydrogen annealing process prior to the sputtering deposition on via openings is also investigated to realize good conductivity through the via. This process results in the reduction of copper oxide at the surface of copper film. Using these newly developed processes, 0.2 µm node BiCMOS LSI with 4 level copper interconnects was successfully fabricated and high performance of the copper interconnect system was clearly demonstrated.

Low-temperature growth of boron carbide coatings by direct current magnetron sputtering and high-power impulse magnetron sputtering

“…Therefore, abruptly decreasing coating thicknesses at the slope and the bottom of the grooves are expected not only in DCMS mode, but also in HiPIMS mode, since an enhanced ionization of sputtered target material is not apparent as outlined above. The step coverage was also shown to be influenced by the particle mean free path, which in turn is affected by the Ar pressure [41][42][43]. Saito et al [42] varied the process pressure and demonstrated that a particle mean free path resembling the target-to-substrate distance yielded the best step coverage.…”

“…The step coverage was also shown to be influenced by the particle mean free path, which in turn is affected by the Ar pressure [41][42][43]. Saito et al [42] varied the process pressure and demonstrated that a particle mean free path resembling the target-to-substrate distance yielded the best step coverage. In our study, Ar pressures between 500 and 800 mPa result in a Figure 2 Growth rates as a function of the process pressure for B 4 C coatings deposited at the substrate temperatures of 100°C (black) and 400°C (red) using DCMS (squares) and HiPIMS (triangles).…”

Effect of Process Parameters on the Angular Distribution of Sputtered Cu Flux in Long-Throw Sputtering System

“…To obtain a conformal film in the high aspect ratio via structure, the angular flux of the sputtered Cu toward to the bottom of the deep via needs to be enhanced to produce a relatively thick film at the contact bottom [6]. As the distance between target and substrate increases, the range of the angle of the atomic flux that is reaching the substrate is decreased naturally such that the deposition can be added to the bottom of the structure [7,8].…”