Amorphous silicon ͑a-Si͒ was crystallized by femtosecond laser annealing (FLA) using a near-infrared ͑ Ϸ 800 nm͒ ultrafast Ti:sapphire laser system. The intense ultrashort laser pulses lead to efficient nonlinear photoenergy absorption and the generation of very dense photoexcited plasma in irradiated materials, enabling nonlinear melting on transparent silicon materials. We studied the structural characteristics of recrystallized films and found that FLA assisted by spatial scanning of laser strip spot constitutes superlateral epitaxy that can crystallize a-Si films with largest grains of ϳ800 nm, requiring laser fluence as low as ϳ45 mJ/ cm 2 , and low laser shots. Moreover, the optimal annealing conditions are observed with a significant laser-fluence window ͑ϳ30% ͒.

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A model based on statistical method and elastic theory is presented to describe the wear mechanism of the silicon wafer surface during chemical-mechanical polishing. This model concerns the effects of applied pressure and relative velocity between the pad and the wafer on the removal rate during polishing and is capable of delineating the role of the mechanical properties of the slurry particles and the films to be polished. The removal rate is dependent on the elastic moduli of slurry particle and polished film. Comparisons with experimental data demonstrate the validity of the model for predicting relative removal rate for various dielectric films.

In the study, the film properties and chemical mechanical polishing (CMP) characteristics of the low‐dielectric‐constant materials hydrogen silsesquioxane (HSQ) and methyl silsesquioxane (MSQ) were presented. The Fourier transform infrared spectra, refractive index, dielectric constant, and atomic force microscopy results showed the successful preparation of the HSQ and MSQ films. The CMP characteristics of both materials were studied by two different ZrO2‐normalbased slurries, A‐1 and B‐1. Our results showed that the CMP removal rate and nonuniformity increased with increasing the slurry solid content. The removal rate of the polished HSQ film was much larger than that of the polished MSQ film due to the hydrophobic surface of the MSQ film. The removal rate using the A‐1 slurry was larger than the B‐1 slurry for polishing both films. This result can be explained from the consideration of the isoelectric point and the electrostatic force between the abrasive surface and the film surface. The downforce pressure of the CMP process also showed a significant effect on the removal rate and the nonuniformity of the polished HSQ film. © 1999 The Electrochemical Society. All rights reserved.