Conventional Polishing Methods Research Articles

Precise SEM Cross Section Polishing via Argon Beam Milling

Abstract SEM observation of a specimen cross section can provide important information for research and development as well as failure analysis. In most cases, surface observation alone cannot provide information concerning the cross sectional structure of granular materials, layered materials, fibrous materials, and powders. Preparing highly-polished cross sections of these materials is both a science and an art. Typically, a cross section is prepared using mechanical means like conventional mechanical polishing methods or a microtome. The sample is first embedded in a holder or device, and then polished to achieve a flat cross section. In some cases, a staining procedure is used to highlight a specific component of the sample. Such methods can be lengthy procedures that require a great deal of skill, and can introduce artifacts into soft materials, deform the material around voids, or compress layers of soft and hard materials in composite samples. Mechanical polishing can miss fine details such as the presence of hairline cracks, and present a challenge to water-soluble phases.

Evaluation of Cleanability of a Titanium Dioxide(TiO2) -coated Acrylic Resin Denture Base

Purpose: The purpose of this study was to evaluate the cleanability of a titanium dioxide (TiO2)-coated acrylic resin denture base.Materials and Methods: Two groups of acrylic resin denture base plate specimens were prepared: 1) the TiO2-coated group, and 2) the Polished group made using a conventional polishing method. The surface roughness and contact angle of plate specimens from both groups were measured. Each plate was immersed in an experimental bolus. Subsequently, the amount of experimental bolus residue left on the surfaces of the plates after ultrasonic cleaning was compared between groups. The groups were further divided into two groups with and without ultraviolet-A ray irradiation during cleaning.Results: The surface roughness of the TiO2-coated group was greater than that of the Polished group. Inversely, the contact angle of the TiO2-coated group was smaller than that of the Polished group (one-tenth that of the Polished group). There was a significant reduction in the experimental bolus residue ratio on the surfaces of the TiO2-coated plates. The use of ultraviolet-A ray irradiation was not significantly different. The decrease in the experimental bolus residue ratio of the TiO2-coated group was believed to be due to the considerable improvement in the wettability of the plates.Conclusion: The TiO2 coating on an acrylic resin denture base had a positive effect on its ease of cleaning by preventing the accumulation of experimental bolus residue.

A miniaturized biconvex quartz-crystal microbalance with large-radius spherical thickness distribution

A miniaturized biconvex quartz-crystal microbalance (QCM) with large-radius spherical thickness distribution was fabricated by reactive ion etching (RIE) and photoresist reflow with solvent vapor technology. A conventional polishing method could not manufacture the miniaturized, spherically convex shape, which is necessary to suppress a spurious mode and obtain a high Q factor. Not only can the large-radius spherical convex shape be achieved by this technology, but also miniaturization and batch fabrication. The Q factor of the fabricated QCM (80 000) is two times higher than that of the planar QCM, and the spurious mode around the fundamental vibration mode is suppressed very well. It also has superior resonant characteristic under the viscoelastic liquid.

電界機能性流体を用いた精密研磨技術(J23-2 マイクロナノ理工学(2),J23 マイクロナノ理工学)

The new polishing method to easily control to make arrangement of abrasive particles onto the polishing area using functional fluid under low frequency AC electric field are developed. In this method, we introduced the multi-layered concentric electrode to previous method for polishing of relatively thick and nonconductive material plates as glass and semiconductor. It is clarified that the motion of abrasives can be controlled by AC electric field on the basis of in-situ observation during polishing. After choosing of optimum polishing conditions, borosilicate glass plates were polished. That surface roughness was reduced from 13.5nmRa to 7.5nmRa after 3min. The multi-layer concentric electrode showed about 1/5 treatment time shorter than the conventional polishing method without AC electric field.

A new elegant technique for polishing CVD diamond films

It is well known that the columnar growth nature of CVD diamond results in a very rough growth surface and the surface roughness steeply increases with film thickness, especially for thick CVD diamond films. In this paper, we report the successful implementation of a new elegant technique for polishing thick polycrystalline CVD diamond films at high polishing rate of up to 10 μm/h. This technique involves polishing the as-grown polycrystalline diamond films with another thick as-grown polycrystalline diamond film, which acts as a polishing abrasive. Two types of diamond films were prepared using microwave plasma CVD and then polished for 2 h using the new polishing technique. A stylus profilometer, scanning electron microscopy and Fourier transform infrared spectroscopy were used to measure the surface roughness, characterize morphology and optical transmission of the samples before and after polishing, respectively. By polishing, thickness of 20–30 μm was removed from the top surface, and the mean surface roughness R a of the films reduced significantly, e.g. for one film R a reduced initially from 5.2 to 1.35 μm and the other from 3.2 to 0.55 μm. The principal advantages of this new polishing technique are simplicity, flexibility and time saving. This simple method can serve as ‘rough chipping’ to quickly remove the rough top surface and then combine with conventional polishing methods for precision machining to further reduce the surface roughness to a specific desired degree.

Characterization of a New Cleaning Method Using Electrolytic Ionized Water for Polysilicon Chemical Mechanical Polishing Process

In trench isolation technology, the surface layers of poly-Si buried in the trench are contaminated with silica particles and chemical impurities by the conventional chemical-mechanical polishing (CMP) method. These contaminations produce some unexpected patterns and crystal defects in the wafer surface layer after oxidation. Furthermore, it is difficult to remove them by the conventional wet cleaning techniques. In this work, we have established a new post-CMP cleaning method, using electrolytic ionized water containing a small quantity of HCl. The anode water is shown to have a cleaning effect on the metallic and organic contamination, whereas the cathode water is shown to have a removing effect on the particles and an etching effect on the poly-Si surface. We present the optimization results of the post-CMP cleaning condition by investigating the surface-related properties by means of a particle counter, ellipsometry, secondly electron microscopy (SEM), atomic force microscopy (AFM), inductively coupled plasma/mass spectroscopy (ICP/MS), and secondary ion mass spectroscopy (SIMS). Our newly established cleaning method is currently applicable to the actual CMP planarization process for VLSI.

Proposal of Mirror Finishing Technology without Using a Polishing Pad. Development of 4-Body Finishing Technology Using Polymer Particles.

A polishing pad has so far been indispensable in conventional polishing method for most industrial materials. However, many problems, such as wear and glazing of pad surface, variation in removal rate over time, poor repeatability and difficulty in process control, and necessity of in-situ conditioning of pad surface, remain to be solved. A mirror polishing method using no polishing pad is therefore proposed, in which polymer particles are supplied together with abrasive grains on to a tool plate that could be made of hard materials. The polymer particles serve as countless micropads in the work-to-plate gap for polishing action, as well as spacers preventing contact between the tool plate and the workpiece. The feasibility of this method has been verified through polishing experiment of silicon wafers. Higher removal rate of material and higher form accuracy, easier process control and higher stability at less polishing resistance, and hence lower power consumption have been obtained than using a polishing pad. Also it is found that the properties of polymer particles and the surface roughness of tool plate have very important effects on polishing characteristics.

Surface texture evaluation of glass ionomer restorative materials polished utilizing poly(acrylic acid) gel

This study evaluated the surface texture of three different glass ionomer restorative materials and a composite resin, polished by a new method using poly(acrylic acid) gel. Conventional polishing methods and finishing agents were compared to the proposed new procedure. Evaluations were carried out employing three techniques: profilometry, scanning electron microscopy and microhardness testing. The use of a poly(acrylic acid) gel with polishing discs gave significantly better results, and is therefore recommended for clinical applications.

Improvement of Conventional Polishing Conditions for Obtaining Super Smooth Surfaces of Glass and Metal Works

Summary In order to ensure the super smooth surface on specific optical devices used in short wavelength optics, a conventional optical polishing method has been improved. taking account of mechanical actions of abrasives, dusts and polisher surface structure. Soft tools as polisher. for instance pitches, waxes and new plastics, were applied to finish of fused quartz, stainless steel, etc. In pitch polishing, worked surfaces with fine abrasive powders and these mixed with coarse hers as a dust model were compared. By using the harder pitch polisher, surface roughness becomes the larger and its tendency is remarkable under dust conditions. Fused quartz works was polished with smooth fluorocarbon foam polisher instead of pitch polisher. Surface roughness value reachs less than 1 nm Rmax with CeO2 powders. Under careful condition for dust, its value results in less than 0.5 nm Rmax with good success in using fluorocarbon foam polisher and fine SiO2 powders.

熱化学反応を利用した膜状ダイヤモンド研磨機の試作および性能

In recent years, synthesizing diamond film from gas phase is expected to be a new method of surface hardness improvement. Since the diamond film has a rough surface, it may be necessary to be polished. But the adhensive strength between the film and the substrate is too weak to endure the force produced by the conventional polishing method using diamond powders, so some new polishing method is needed. In this study, using the thermo-chemical reaction between diamond and iron, a polishing apparatus is manufactured for trial. A diamond film deposited on a 7 × 7× 4 mm silicon substrate by microwave plasma CVD is used as a workpiece, an iron plate heated to 810°C is used as a polishing plate, the polishing pressure of 60 kPa is much smaller than that of the conventional method, and the polishing experiment is performed in a hydrogen gas atmosphere. After 2 hours' polishing, the diamond surface becomes smooth without any exfoliation.

Applications of Diamond Turning to Infrared Optical Systems

Diamond turning is immediately applicable to the fabrication of infrared optical components because presently available machines can meet the reduced absolute accuracies required at 10 micrometers. An initial survey of infrared sensor programs at the Honeywell Radiation Center has been conducted to predict the near term and future demand for diamond-turned optical components. Not only does the fabrication process promise significant cost savings as compared to conventional lapping and polishing methods, but, as in the case of aspheric lenses, wider applications are also sought to reduce weight and space requirements. In addition, broader usage of diamond-turned aspherics reduces total parts count and assembly and alignment time, provided proper tools and test equipment are employed. The potential cost savings of diamond-turned vs conventionally fabricated optics are summarized for contracts at the Radiation Center. The savings were calculated by subtracting the difference in fabrication costs and multiplying by the number of items expected to be produced into the mid-1980s. Technical fallout potential of the diamond-turning process is also noted in the apparent ability of a coated sample to pass a 24-hour salt fog test.