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Abstract: Heat is an indispensable factor in understanding the removal rate and WIWNU (within wafer non-uniformity) in CMP (chemical mechanical polishing). The principal heat generation mechanism results from the two-body abrasion mode. Experiments are implemented using the on-machine temperature measuring system with an IR digital camera. This paper investigates the primary process parameters affecting heat generation and temperature distribution on pad surfaces. Meanwhile, the change of temperature affects the characteristics of both slurry and pads. The change in the pH value of the slurry due to the alteration of temperature affects the surface state of the abrasive particles and therefore the agglomeration of abrasives happens above a certain temperature. Moreover, the temperature changes the first and second elastic moduli of the pads and their real contact area, which is closely related to the removal rate and WIWNU. [Copyright &y& Elsevier]

Chemical mechanical polishing (CMP) is the process of planarization which was achieved by both chemical reaction and mechanical force. The polishing consists of moving wafer to be polished against the polyurethane pad, carrying slurry between wafer and polyurethane pad. There have been, however, some problems including dishing, erosion, high cost of consumables, environmental problems and scratches due to diamonds dropped out of conditioner. In particular, the slurry used in CMP not only increases the cost of consumables, but also interferes with the environmentally benign semiconductor manufacturing. This paper introduces the encapsulated abrasive pad to achieve the environmentally benign CMP and self-conditioning mechanism of pad. The self-conditioning just means that additive conditioning process on pad is not necessary between polishing wafers. Hydrophilic polymers were used to develop the encapsulated abrasive pad. When these polymers keep in contact with water, they have soluble and swelling characteristics. The removal rate of the encapsulated abrasive pad showed higher than that of general CMP process using slurry and polyurethane pad. The self-conditioning of pad was verified through experiment, which showed the possibility of environmentally benign process only using de-ionized water in interlayer dielectric CMP. [Copyright &y& Elsevier]

Abstract: Micropatterned thin films when planarized using chemical mechanical polishing (CMP) accompany several inherent problems, especially dishing defects. The deteriorations in surface planarity limit the accuracy and flexibility of next fabrication steps, thus accounting for a major portion of yield losses in the mass production of microelectronic components. A hybrid polysilicon (poly-Si) planarization using a protective dioxide (SiO2) film and two slurries having diametrically opposite poly-Si-to-SiO2 selectivity is developed to suppress dishing defects in the CMP of patterned poly-Si films. A 30nm-thick protective SiO2 film is deposited on a patterned poly-Si film to protect recessed areas on the uneven poly-Si film; the SiO2-protected poly-Si film is planarized with the first slurry having low material selectivity to selectively remove the protective SiO2 film placed on protruding areas while effectively remaining it located on recessed areas; the primarily planarized poly-Si film is polished again with the second slurry having high material selectivity to minimize the amount of dishing defects. For diverse poly-Si layers having different pattern widths of 5–90μm, the dishing amount is measured less than 23.1nm after the hybrid poly-Si planarization, and noticeably the dishing amount is insensitive to the pattern width. This shows that our hybrid poly-Si planarization can improve the planarity of each poly-Si film in the fabrication of multi-level (or three-dimensional (3D)) microdevices. The dependence of the material removal rate of poly-Si films on critical slurry parameters such as slurry pH and abrasive concentration is also intensively discussed. [Copyright &y& Elsevier]

Abstract: The pad roughness plays a key role in material removal in oxide chemical mechanical polishing (CMP) process. Its variation also has an effect on within wafer non-uniformity. The R pk among roughness parameters, which is related to pad wear characteristics, was investigated to find the correlation between spatial roughness distribution of a polishing pad, and material removal profile in CMP, using two different types of slurries. The removal rate of ceria-based slurry for STI CMP was higher in the wafer center than that of the silica-based slurry. This is because the pad roughness distribution in a convex shape is formed across the pad radius in the contact area between pad and wafer instead of the degradation of pad roughness during CMP. Also, there is an increase of R pk results in the increase of average friction force by comparison with the decrease of friction force in CMP using silica-based slurry. This result may be expected as the effect of the chemical tooth of ceria abrasive and slurry accumulation in the wafer center causes a roughening of the pad surface just as sandpaper. [Copyright &y& Elsevier]