Sapphire (alpha-Al2O3) is an important ceramic material that is widely used in substrate material for electronics. We investigate the chemical reaction layer on a sapphire wafer using X-ray photoelectron microscopy (XPS) and atomic force microscopy (AFM). The frictional characteristics of sapphire chemical mechanical polishing (CMP) was studied using in-situ friction force monitoring system. From XPS analysis and AFM experiment, a chemically-reacted layer was verified on the sapphire surface through a chemical reaction between the sapphire and chemicals in a slurry. During sapphire CMP, the friction force mainly depended on the applied pressure. The material removal efficiency per unit friction energy in sapphire CMP was 6.18 nm/kJ.

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A simplified model related to microtopography on CMP pad and prediction of real contact area between the pad and wafers is presented in this paper. The model has been developed on the basis of the analysis of the pad surface roughness and contact mechanics. The bearing area curve, representing tribological properties of the surface, is used to formulate the model. The pad microtopography which is expressed in the model is uniform and simple. Particularly, the important characteristics of the pad microtopography for the CMP process are emphasized in the model. It provides more convenient way to perceive the situation of the pad surface during the CMP process. The progress of the pad surface wear and the real contact area can be easily taken and connected each other by using the model. The model is also verified by comparing the tendency of actual removal rates with those theoretically anticipated. Finally, authors could get the efficient link between the pad surface wear and the real contact area, which results in a strong tool to understand the fundamental CMP mechanism of material removal.

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Recent years have seen a great deal of progress in the development of transmission electron microscopy-based techniques for strain measurement. Dark-field electron holography (DFEH) is a new technique offering configuration of the off-axis principle. Using this technique with medium magnification (Holo-M), we carried out strain measurements in nanoscale-triangular SiGe/(001) Si with (004), (220) and (111) diffraction spots. The reconstruction of holograms and interpretation of strain maps in term of strain precision were discussed and the strain distributions in the SiGe/(001) Si patterns were visualized. Based on linear anisotropic elastic theory for strain simulation, the simulated results obtained by the finite element method compared with the experimental results acquired by DFEH. The strain values were found to be 0.9-1.0%, 1.1-1.2% and 1.0-1.1%, for the (004), (220) and (111) diffracted beams, respectively, and the strain precisions were determined to be ~2.1 × 10, 3.2 × 10 and 9.1 × 10 for the corresponding diffraction spots. As a result, DFEH is highlighted as a powerful technique for strain measurement, offering high-strain precision, high-spatial resolution and a large field of view.