Abstract: In-line thickness measurement of a dielectric film layer on a surface of a workpiece subsequent to a polishing on a chemical-mechanical polishing machine in a polishing slurry is disclosed. The workpiece includes a given level of back-end-of-line (BEOL) structure including junctions. The measurement apparatus includes a platen and an electrode embedded within the platen. A positioning mechanism positions the workpiece above the electrode with the dielectric layer facing in a direction of the electrode. A slurry dam is used for maintaining a prescribed level of a conductive polishing slurry above the electrode, the prescribed level to ensure a desired slurry coverage of the workpiece. A capacitance sensor senses a system capacitance C in accordance with an RC equivalent circuit model, wherein the RC equivalent circuit includes a resistance R representative of the slurry and workpiece resistances and the system capacitance C representative of the dielectric material and junction capacitances.

Abstract: Electrically conducting vias and lines are created by a three step process. First, a controlled amount of a soft, low resistivity metal (12) is deposited in a trench or hole to a point below the top surface of the dielectric (10) in which the trench or hole is formed. Subsequently, the low resistivity metal (12) is overcoated with a hard metal (16) such as CVD tungsten. Finally, chemical-mechanical polishing is used to planarize the structure. The hard metal (16) serves the function of protecting the low resistivity metal (12) from scratches and corrosion which would ordinarily be encountered if the low resistivity metal were subjected to the harsh chemical-mechanical polishing slurries. An ideal method for partially filling trenches or holes in a substrate is by sputtering at elevated temperatures such that metallization at the bottom of a trench or hole separates from metallization on a top surface adjacent the trench or hole.