Papers by Keyword: Polishing

Abstract: This article reviews the state-of-the-art techniques for polishing diamond and polycrystalline diamond composites. A focus is on their material removal mechanisms and features. It concludes that while each of them has its advantages and drawbacks, the technique by dynamic friction has a promising potential for polishing production.

Abstract: Expected path of polishing tool is one of the most essential needs for movement scheduling and movement controlling of polishing robot in free-form surfaces polishing. By analyzing the expected movement and position of polishing tool and based on the traditional movement scheduling methods, this paper carries out systematic research works on contour-parallel-machining tool path planning method and direction-parallel-machining tool path planning method for polishing tool paths figuring out. Compared with contour-parallel-machining tool path planning method, the direction-parallel-machining tool path planning method needs one less number of degree of freedom and is much easier to avoid physical interventions and mechanic singularity, so it is an improved one.

Abstract: The influence of the chemical mechanical planarization process on the 4o off-axis 4HN SiC removal rate for silicon carbide slurry produced by Cabot Microelectronics Corporation (CMC) has been studied. A detailed kinetic analysis was applied and the linearity of an Arrhenius-like activation energy plot suggests that the primary removal occurs from particles adhered to the pad surface.

Abstract: A novel chemical planarization method was developed for silicon carbide (SiC) and gallium nitride (GaN). This method uses catalytically generated hydroxyl radicals (OH*) to oxidize the wafer surface. OH* are generated by the reductive decomposition of hydrogen peroxide (H2O2) on the surface of the iron reference plate. An extremely flat surface without pits or scratches was obtained. Atomic force microscopy (AFM) revealed that the planarized surface had an atomic step-terrace structure, in which the step height corresponded to a single bilayer of 4H-SiC and GaN. Low electron energy diffraction (LEED) and cathodeluminescence spectroscopy showed that there was no crystallographic damage on the planarized surface.

Abstract: This paper experimentally investigates the effect of time and pressure on the condition of polishing pads and the material removal rate (MRR) of single crystal silicon. It was found that as the pad deteriorates with time, MRR decreases. Surfaces with a required quality can only be achieved before the texture deterioration reaches a critical limit. At a higher pressure, 25 kPa, deterioration is slower, and the effective life of pads and MRR is enhanced.

Abstract: This paper experimentally investigates the micro-structural changes in mono-crystalline silicon induced by abrasive polishing with abrasive grain size and applied pressure. It was found that while the large abrasives of about 15 μm and 300 nm in diameter induce both residual amorphous phase and various residual crystalline structures and dislocations, the finer abrasives of about 50 nm in diameter only produce residual amorphous phase in the top subsurface of polished silicon. With the fine abrasives, reducing applied pressure reduces the amorphous layer thickness, and a damage-free polishing can be achieved at the pressure of 20 kPa.

Abstract: This paper deals with the machining of quartz wafers using an MCF (Magnetic Compound Fluid) polishing liquid, frozen with liquid nitrogen. This type of polishing liquid is composed of water-based MF (Magnetic Fluid), iron powder, abrasive particle and α-cellulose, and consequently reacting to magnetic fields. Experiments of polishing quartz wafers using the MCF method were carried out on a previously developed apparatus. The results show that an MCF polishing liquid, frozen with liquid nitrogen, has greater material removal capability than one that has not been frozen. A frozen MCF polishing liquid containing larger abrasive particles yields a higher material removal rate, however the surface roughness deteriorates. The highest material removal rate and the best surface roughness were obtained when the percentage of water, in the frozen MCF polishing tool, was 34.7%.

Abstract: The paper presents a newly developed optical polishing method, Ultrasonic-magnetorheological compound finishing (UMC finishing). The mechanism of UMC finishing is introduced in the paper. Experiments are carried out to study the surface quality of the optical glass K9 in UMC finishing. The result shows that the surface roughness Ra of the optical glass is 4.0nm, which is measured by the profile meter. The rules of surface roughness for optical glass by the main processing parameters are also acquired by the experiments. The study will be the basis for the further study of UMC finishing technology.

Abstract: The purpose of this study is to fabricate a wheel using fullerenes with nano-scaled particles, and to investigate the polishing performance of fullerene wheel. A super smooth surface was formed on a silicon wafer by polishing the wafer with metal-bonded diamond wheels using a diamond abrasive grit of 0-0.125 μm and fullerenes with a diameter of 0.7 nm. We used two kinds of metal-bonded diamond wheels for pre-polishing and a metal-bonded fullerene wheel for the finishing process. Though the surface roughness after polishing with the fullerene wheel was almost equal to that obtained by polishing with the metal-bonded diamond wheel using diamond abrasive grit of 0-0.125 μm, the chemical-mechanical polishing process was clarified by AFM (atomic force microscope) observation when we used a metal-bonded fullerene wheel with 5wt% KOH (potassium hydroxide) solution. The greater number of smoothed portions on the surface of the silicon wafer indicated that the fullerenes provided the same polishing ability as that of the abrasive grit.

Abstract: We developed a nanoparticle colloid jet machining to fulfill the requirement for ultrasmooth surface in terms of the studying on micro structure of work surface, the high surface energy and intense adsorption of SiO2 nanoparticle. In this paper, three types impact in nanoparticle colloid jet machining have been analysed and the atom removing model has been founded based on the physical chemistry theory of solid surface and interface. The factors which may influence the nanoparticle colloid jet machining quality (such as the diameter of nanoparticle, colloid jet velocity and dynamical viscidity) have been studied to provide theoretical support for further studying in nanoparticle colloid jet machining.