Tribological Effects of Brush Scrubbing in Post Chemical Mechanical Planarization Cleaning on Electrical Characteristics in Novel Non-porous Low-k Dielectric Fluorocarbon on Cu Interconnects

Abstract

Damage reduction during planarization is strongly required to avoid scratch generation and the variation in the electrical properties of low-k dielectrics leading to yield loss in an integrated circuit after the implementation of an ultralow-k dielectric in Cu damascene interconnects. An optimum process condition to reduce damage on brush scrubbing in post-chemical–mechanical-planarization (post-CMP) cleaning was proposed for advanced nonporous organic ultralow-k dielectric fluorocarbon/Cu interconnects. Increasing brush rotation rate by decreasing down pressures results in the improvement in both electric properties and particle removal efficiency. The tribological effects of brush scrubbing in post-CMP cleaning on the electrical characteristics were explored. The brush scrubbing condition of a high brush rotation rate at low down pressures contributes to the suppression of damage generation.

Integration Process Development for Improved Compatibility with Organic Non-Porous Ultralow-k Dielectric Fluorocarbon on Advanced Cu Interconnects

“…21,22) A high brush rotation at a low applied down pressure of brush scrubbing cleaning condition, which has been reported to satisfy both good electrical properties and particle removal efficiency, was used for the post-CMP cleaning. [23][24][25] Finally, a passivation SiCN film was formed, then a final annealing treatment was applied at 150 C.…”

Tribological Study of Brush Scrubbing in Post-Chemical Mechanical Planarization Cleaning in Non-porous Ultralow-k Dielectric∕Cu Interconnects

“…Similar variances of electrical results in fluorocarbon/Cu damascene interconnects were also certified in our previous result. 17 Brush contact kinematics and hydrodynamic effects.-To clarify the mechanism of shear force generation, the dynamic contact kinematics of the brush on the Cu wafer were inspected by means of the pressure sensing sheet and an ultra high speed camcorder in the dry condition. Pictures of the brush nodules in contact with the wafer taken by the ultra high speed camcorder (>2000 fps) and corresponding maps of pressurized sensor cells of the pressure sensing sheet are shown in Figs.…”

“…A 100 nm-thick Cu film on a 30 nm-thick titanium nitride (TiN) film was deposited on a 200 mm-diameter silicon substrate by physical vapor deposition for a measurement of shear force and study of contact characteristics by the pressure sensing sheet. [15][16][17] Figure 1a illustrates the top view of the brush scrubber with the brush and wafer rotation mechanisms. Although upper and lower brushes are installed on this equipment, only the upper one is shown in Fig.…”

“…A pressure-sensing sheet has been proposed by the authors to study dynamic contact behavior. [15][16][17] The pressure sensing sheet with a 0.1 mm thickness, consisting of a thin semiconductive sheet as the intermediate layer between row and column conductive electrodes, was placed between the rotating brush and the wafer, then a study of dynamic contact behaviors during the brush scrubbing process was examined.…”

Advanced Direct-Polishing Process Development of Non-Porous Ultralow-kDielectric Fluorocarbon with Plasma Treatment on Cu Interconnects

“…21,22 An advanced brush scrubbing process with a high brush rotation rate (500 rpm) in low applied down-pressure (5.5 kPa) was applied as a post-CMP cleaning process. [23][24][25][26] Finally, a passivation film was deposited, and then an annealing treatment was applied at 150 • C with 1 h. To clarify the impact of the direct-polishing process on the fluorocarbon film, blanket samples were also prepared to evaluate electrical characteristics of fluorocarbon film in a metal-insulator-semiconductor (MIS) structure. For the MIS structure, a 100 nm thick fluorocarbon film with or without post-deposition N 2 plasma treatment (NPT), carried out at a microwave power of 2 kW by N 2 /Ar gases as flow rates of 80/20 sccm for 15 s, was prepared on the 200 mm diameter silicon substrate, followed by a 30 nm thick TiN film formation, as shown in Fig.…”