| Summary: | 碩士 === 國立中興大學 === 機械工程學系 === 90 === ABSTRACT
Chemical mechanical polishing (CMP) is the most commonly used process in the planarization of wafer surfaces. This thesis, from the stress viewpoint, investigates the effects of intrinsic stress and extrinsic stress on the removal rate of copper CMP. The former is the stress from the sputtering and annealing processes while the latter is the stress occurred in the polishing process.
Three types of experiments are designed and conducted in this thesis, including chemical corrosion, mechanical polishing, and CMP. Achievement of this study includes the following items: (1) The copper film after sputtering and annealing sustains tensile stress that intensifies corrosion rate. (2) Film stress increases after annealing. For copper film with 1,000 nm and 2,000 nm in thickness, the stress increases as the annealing temperature increases. For film of 1,500nm in thickness, the stress decreases with the annealing temperature. The corrosion rates of films with annealing temperature at 150°C and 250°C increase with film stress. But the rate decrease with film stress for copper film annealed at 200°C. (3) The stress of 1,000nm thick copper film increases at high annealing temperature. Meanwhile, the corresponding corrosion rate increases. (4) Continuous polishing on 1,000nm copper film showed that the removal rate increases rapidly. The removal rate is strongly dependent upon film stress under this condition. (5) The removal rate of mechanical polishing, however, is relatively low. As the rate is less than 20Å/min, it indicates that the removal mechanism of CMP is not a simple superposition of chemical corrosion and mechanical polishing.
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