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Mechanical Polishing (mechanical + polishing)

Distribution by Scientific Domains
Physics and Astronomy66%

Selected Abstracts

CMP wastewater management using the concepts of design for environment

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2002
Gordon C. C. YangArticle first published online: 20 APR 200
Application of design for environment (DfE) concepts to management of wastewater from chemical mechanical polishing (CMP) processes are presented in this paper. Today, DfE is a prevailing concept and is widely adopted by advanced nations in lieu of the traditional "command and control" approach to control waste and toxic emissions. Designing environmentally-benign processes and products is a new and challenging frontier for engineering professionals, including those in the semiconductor industry. An insatiable need for water and subsequent wastewater treatment has imposed a chilling effect on semiconductor industry growth. It was estimated that semiconductor producers consumed more than 5.523 × 108 m3 of water in 2000. Of this amount, CMP processes accounted for 40% of the total. The CMP tool market and CMP slurry market are estimated to have 36% and 29% annual growth rates, respectively between 2000 and 2005. Inevitably, a tremendous amount of waste slurry and post-CMP rinse water will be generated and have to be managed properly. CMP wastewater is characterized by its high content of suspended solids having sub-micron particle sizes, high turbidity, and high conductivity. Traditional wastewater treatment technologies, such as chemical coagulation/precipitation, do not work well for CMP wastewater, because it would generate a large volume of sludge, which might cause disposal problems in many countries, such as Taiwan. Therefore, utilizing pollution prevention principles in the design of CMP tools, development of new CMP slurries, and improved plant operations are necessary to minimize environmental damage. Reclamation of process water is also a common requirement in the semiconductor industry. To this end, several alternatives for source reduction of CMP wastewater and water reclamation are presented in this paper. [source]

Damascene Process for Controlled Positioning of Magnetic Colloidal Nanocrystals

ADVANCED MATERIALS, Issue 12 2010
Gang Chen
Nanocrystals, deposited on Si wafers, are maneuvered into sub-100-nm-sized pits or grooves by a Damascene process, that is, dropcasting and subsequent mechanical polishing. Single occupation is demonstrated for magnetic nanocrystals with diameter down to 18,nm. The figure show scanning electron microscopy and magnetic force microscopy images for a set of pits occupied by single Fe3O4 magnetic nanocrystals with 50-nm size. [source]

Depth profiling of optical and vibrational properties in GaN/AlN quantum dot superlattices

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2009
A. Cros
Abstract Spatially resolved confocal ,-Raman and ,-photoluminescence experiments were performed to analyze the vibrational and optical properties of GaN/AlN quantum dots as a function of depth. Two approaches have been followed. First, spectra were taken by defocusing the microscope objective at various depths on the sample surface. In a second set of experiments a bevel at an angle of 20° with respect to the surface normal was prepared by mechanical polishing of the surface, and spectra were taken across the bevel. The E2h vibrational modes ascribed to the GaN QDs and the AlN spacer redshift towards the surface, indicating the progressive relaxation of the QDs and a considerable increase of the tensile strain in the AlN spacer. The photoluminescence is found to blueshift and narrow towards the surface. This behaviour is ascribed to the decrease of the QD internal electric field as a consequence of the relaxation. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Characterization of MOCVD grown GaN on porous SiC templates

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005
F. Yun
Abstract We have grown GaN layers by MOCVD on a set of nanoporous SiC templates with different porosity and morphology, produced by etching the anodized porous SiC starting material in a H2 environment at temperatures ,1500 °C, in an effort to attain improved films. The hydrogen etching serves to remove surface damage caused during mechanical polishing prior to anodization, remove the skin layer associated with anodization, tune the pore size, and consolidate pore geometry. Growth conditions favoring lateral overgrowth of GaN were employed on this set of samples to obtian GaN to a thickness of 2 µm. Atomically smooth surfaces were obtained for the epitaxial GaN layers. The GaN quality is highly dependent on the specifics of the porous templates used. An intensity increase of up to a factor of 30 was observed in the GaN excitonic peak compared to GaN grown on standard SiC substrate. The I-V data indicated significant reduction in the leakage current (in reverse bias) compared to GaN grown on standard SiC. The dependence of optical properties, crystalline quality, and surface morphology on the particulars of porous SiC templates is discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Chemical mechanical polishing for decoration and measurement of dislocations on freestanding GaN wafers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003
Xueping Xu
Abstract The dislocation density in freestanding gallium nitride wafers was measured using atomic force microscope (AFM) imaging of chemical mechanically polished (CMP) samples and with transmission electron microscopy (TEM). Etch pits were introduced after chemical mechanical polishing of the gallium side of the GaN wafer and the pits easily imaged with the AFM. TEM was also utilized to measure the dislocation density. Good agreement was found between the dislocation density measured by TEM and the etch pit density measured by AFM, demonstrating that chemical mechanical polish of the GaN(0001) surface decorates threading dislocations and that the AFM technique provides a reasonably accurate and convenient measure of the dislocation density. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]