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This book on nanodiamonds is the first of its kind. Nanodiamonds are indispensable for polishing industrial materials (e.g., computer hard drives and read heads) and advanced ceramics (e.g., silicon carbide and gem diamond). The book is valuable for those dealing with nanodiamonds as well as for those interested in a general education of nanosize materials.

A graphene/silicon (Si) multilayer sandwich structures are fabricated using electron beam (EB) deposition without air exposure. The graphene and Si thin films are formed on Cu current correctors through a continuous process in high-vacuum EB chamber. Synthesized graphene should be suggested to the stacked multiple layer from Raman analysis. The fabricated multilayer films are used as anodes. In the beginning, the half-cell, which used a seven-layer of each thickness 50-nm graphene and Si film, exhibits good specific capacity retention over 1000 mA h g−1 after 30 charge/discharge cycles. The capacity value changed with the number of graphene and Si layers. In this study, the number of layers that exhibited optimal properties is seven. Morphological investigation showed a fine layer-by-layer structure. The relationship between different thicknesses of graphene and Si is investigated at 7 L. A 100-nm thickness exhibited optimal properties. Finally, the optimal 7 L and 100-nm thick graphene/Si exhibited high discharge capacitance >1600 mA h g−1 at a current density of 100 mA g−1 after 30 cycles. Initial coulombic and reversible efficiencies exceed 84%. The capacity retention (30th/1st discharge value) at 100 nm and 7 L exceeds 90%. Finally, the soft package battery is assembled by combining the fabricated graphene and Si electrode as anode, LiCoO2 as cathode, separator and liquid electrolyte. It can be used for commercial light-emitting diode (LED) lighting even under bending status.

This paper presents a novel lubrication method for milling processes that employs cooling system-assisted minimum quantity lubrication (CSMQL) using a thermoelectric cooling system. The CSMQL method improves the cooling effect in the cutting area and enhances processing quality, in addition to reducing energy consumption. Four different coolant strategies including CSMQL, dry, minimum quantity lubrication (MQL), and wet methods were compared in processing mill die steel (SKD11), which is widely used in industry. Different aspects of the milling performance (e.g. surface roughness, morphology, milling temperature, and milling forces) were investigated using these coolant strategies. The experimental results show that not only is the surface roughness of steel milled using CSMQL better than that of steel milled using dry and MQL methods, but CSMQL also produces fewer tool marks on the workpiece surface. In addition, it was found from observations of chip color that using the CSMQL method reduced the cutting...

The requirement of protective coating to prevent refined metals from reactive environments is very important in industrial and academic applications. Most of the conventional methods used for this purpose introduce several negative effects including increased thickness and changes in the optical, electrical and thermal properties of the metal. In this paper, we demonstrate the coating of graphene films grown by chemical vapor deposition to protect the surface of Ni substrates from air oxidation. In particular, graphene prevents the formation of oxide on the metal surface and protect it from reactive environment. Two methods are adopted to induce oxidation on the graphene coated Ni surface: firstly by heating the specimen in air for several hours and secondly, by immerging into a solution of 31% hydrogen peroxide (H2O2). The specimens have been characterized by X-ray diffraction, Optical micrograph, Raman spectroscopy, X-ray photoelectron spectroscopy and the results indicate that the surface is well protected from the oxidation even after heating the specimen upto max. temperature of 500 °C in air for 3 h. It is also observed that graphene provides effective resistance against H2O2. The detailed analysis of graphene as oxidation resistance against air and H2O2 has been presented.

An approach for synthesizing single crystal silicon carbide at low temperature using liquid phase epitaxy is proposed. A mixture of samarium and cobalt (Sm:Co = 64:36 at.%) was used as a unique solvent in this synthesis process. Electron microscopy indicates the epitaxial growth of single crystal silicon carbide with a thickness of 4 µm over a silicon wafer followed by the formation of polycrystalline silicon carbide and silicon carbide whiskers. Some growth mechanisms are proposed to explain the formation of silicon carbide. It is hypothesized that the single crystal silicon carbide grew from the liquid phase, whereas polycrystalline silicon carbide whiskers grew via the vapor–liquid–solid process.

Surface acoustic wave (SAW) devices based on an aluminum nitride (AlN)/diamond layered structure are attractive due to their high operating frequency. To enhance the operating frequency of a diamond SAW device, we demonstrated one piezoelectric layer on diamond by doping AlN with boron. In this study, highly c -axis-oriented wurtzite boron–aluminum nitride (B, Al)N films were deposited on diamond by a co-sputtering technique. The resulting films exhibit a higher piezoelectric coefficient d 33 and higher Young's modulus than AlN films. Moreover, the greater rigidity of (B, Al)N film further boosts the resonance frequency of a diamond SAW device. Considering the SAW wavelength (λ = 2 μm), the calculated surface acoustic velocities ( V S ) of (B, Al)N on diamond is 8860 m/s that is higher than AlN on diamond (8720 m/s). We also find that the electromechanical coupling coefficient ( K 2 ) of a SAW device based on (B, Al)N on diamond was the same (~ 0.5%) as that of one based on AlN on diamond.

Silicon carbide layers were grown on a Si substrate at a temperature below 1100 °C and pressure of 10 5 Pa. The synthesis was carried out in a tube furnace through cyclic heating process using methane as a carbon source and Sm–Co mixed powder as a solvent. The growth of SiC from rare earth Sm-based solvent is an innovative approach, and Co can promote the formation of solvent during the growth process. The structural and compositional analyses were carried out using X-ray diffraction, electron probe micro-analyzer, scanning electron microscopy and transmission electron microscopy. Results indicated that β-SiC was successfully fabricated on Si (1 1 1) substrate. The heterogeneous nucleation of β-SiC was found to be observed initially at the edge of triangle-shaped sites on Si (1 1 1) surface that formed due to the existence of Co, and then grew and expanded to form β-SiC film. The growth process of SiC via vapour–liquid–solid mechanism was also discussed in this study.

This study reports on the deposition of c-axis oriented boron-aluminum nitride ((B, Al)N) layers on polycrystalline and single crystal (111) diamond substrates using a magnetron co-sputtering system. In this study, the lattice mismatch between (B, Al)N and diamond appears to be an important factor in the mechanism behind the growth of (B, Al)N on diamond. Diamond has a significantly tighter lattice than (B, Al)N, and the single (111) diamond substrate has the same lattice symmetry as that of aluminum nitride (AlN) (0002). X-ray diffractometry and transmission electron microscopy were employed to analyze the microstructure of (B, Al)N films on both substrates, and the results showed a continuous variation in structure, from randomly oriented nano-grains to c-axis oriented columns. In addition, the (B, Al)N film exhibited a thinner, randomly oriented nano-grain layer on single crystal (111) diamond than on polycrystalline diamond.

Most blue light LED chips are made by growing GaN epitaxy on a sapphire substrate. Because sapphire is an insulator, the two electrodes on a conventional LED die must lie on the same side. To improve upon existing technology, several companies are developing vertical stacked LED designs by coating P-type GaN with a reflector (e.g. Ag) that is soldered (e.g. via Au-Sn) to an electrode as the substrate. These techniques have their limitations. In this report, we introduce a methodology to producing a high-powered LED with a thin-film DLC (diamond like carbon) interface that can effectively bridge the semiconductor GaN and metallic substrate. DLC can not only moderate the thermal mismatch, but also to enhance the heat spreading since DLC has a thermal conductivity (475 W/mC) that is significantly higher than even copper. In addition, the metal substrate of the LED can optionally be replaced by a diamond-metal (Ni or Cu) composite that further minimizes the CTE mismatch and boost heat spreading efficacy. Such a DLC LED design can sustain a high drive current so that reduced number of enhanced dies can be used in place of conventional chips for small form-factor general illumination applications.

CMP has been practiced by polishing wafers with white polyurethane pads (e.g. IC1010 manufactured by Dow, formerly Rohm-Haas or Rodel). The white pads contain pores to reduce the contact areas at the interface so the polishing rate is increased by enhanced pressure. Moreover, the pores also serve as the reservoir for storing excess slurry. The pockets of slurry can replenish the consumed abrasive particles at the polishing site. With the down sizing of the Moore's law features on interconnects, the pressure distribution at the interface between wafer and pad must be more uniform lest the delicate circuitry (e.g. 32 nm wide) is scratched during the CMP process. Consequently, pores in the pad are made smaller and pads matrix are becoming softer. However, due to the increased contact area of the softer pads, the slurry supply may be cut off as to cause dry spots of polishing. The rubbing of these dry spots can increase the temperature at the polishing site and destruct the fragile film on the wafer. A new design of black pads has eliminate the need of built in pores. Instead, submicron graphite particles are impregnated in polyurethane matrix. The graphite particles can be plucked off at the polishing site so the contact pressure at the polishing site is increased as if pores are present. Furthermore, graphite particles are hydrophilic so slurry can be retained better than that in water repelling white pad. The wetting can also lubricate the polishing site and allow faster polishing of the wafer without damaging the local circuitry. This reports summarizes various features of the black pads including their CMP performance compared to conventional white pads.

Graphene is the ideal material for many dream applications, such as single electron transistors, field emission sources, light through electrodes, flexible solar cells, wall paper displays, UV light emitting diodes, atomic gas sensors, DNA or antigen wafers, terra hertz surface acoustic wave (SAW) generators and filters...etc. However, a practical method to fabricate meter-sized graphene is still beyond imagination. In this research, we reported a simple technology to harvest large area graphite films by using molten alloy as the catalyst. Each film contains hundreds or thousands layers of graphene. Some stacks of graphene revealed silk-like tenderness with transparent folding lines. This liquid phase epitaxy (LPE) process appears scalable for making graphene layers measured in meter size. This paper also presented many intriguing aspects related to the growth of large graphene.

Diamond's (111) face can grow epitaxial GaN with wurtzite structure. Better still, single crystal AlN can be deposited directly on such diamond surface. Boron doped diamond has the highest mobility of holes, and silicon doped AlN can boost electron mobility. The AlN on diamond is capable to emit ultraviolet (UV) light with high intensity. Such UV light can excite phosphors for the emission of different colors, including white light with balanced RGB distribution. There are many possibilities of making super LED with diamond. Unfortunately, diamond wafers are not available commercially. However, synthetic diamond crystals can be made cheaply by a noval seeding technology (DiaCan{trade mark, serif}). These diamond crystals are embedded in a ceramic matrix to form diamond islands wafer (DIW). DIW is the enabling substrate for making super LED in the near future.

Thin film solar cells have emerged in recent years, in particular, those made of amorphous silicon or CIGS (copper indium gallium sellenide). By tendon of boron doped amorphous diamond with phosphorus doped amorphous silicon, the conversion efficiency may rival that of crystalline silicon. On the other hand, the CdS top layer for CIGS is not only poisonous, but also UV degradable. Amorphous diamond coating with N doping can replace CdS to boost CIGS's efficiency also. Nanodiamond may be sputtered from diamond grit or diamond film as target. The PVD formed nanodiamond layer can be located at the interface between P and N types. In this case, the quantum well effect can allow the production of multiple electrons per incident photon. In addition, the output voltage may be increased due to the wide band gap of nanodiamond.

Diamond disks are indispensable for dressing CMP pads. However, due to the leveling requirement, only a few percents of diamond grits can penetrate the pad. As these few crystals are worn out, the plastic deformation of the pad becomes large relative to the amount of pad is cut. Consequently, the pad becomes highly deformed and loaded with dirt. The polishing rate will then decline; and the scratch rate, increase. A novel technique has been developed to identify the cutting tips and their dulling process. The cutting paths become widen and shallow with more and more deformed pad material. Eventually, fewer and fewer scratch lines are present with most touching diamond pushing deformed pad around. Because there are only a handful of diamond grits that are engaged in cutting pad, the number of working crystals can increased substantially by improving the leveling of diamond tips. This improvement can increase the longevity of diamond disks that paves the way for future CMP of 18 inches wafers scheduled to make the debut in 2012.

A mosaic design of diamond disks that incorporates different cutting characteristics of diamond grits can allow faster polishing of wafers with less pad consumption. Larger diamond grits can make pad asperities with large peak to valley ratios for achieving high polishing rate. On the other hand, Sharp grits can shave the pad effectively as to eliminate the glazed layer. The conventional diamond disks employ similar type of diamond grits across the entire disk. These grits cannot dress and cut the pad with optimization. By combining different types of diamond grits in a cocktail combination, the pad asperities can be controlled to enhance removal rates of the wafer. The glazed layer may also be removed cleaner so wafer defectivity is minimized.

Instead of the sophisticated deposition processes and boron sources reported in literature, the study used the radio frequency magnetron sputtering method to prepare boron-doped diamond-like carbon (DLC) films with p-type conduction. The adopted sputtering targets were composed of boron pellets buried in a graphite disc. The undoped DLC films prepared exhibited n-type conduction, based on the Hall-effect measurement. For boron content ≥ 2.51 at.%, the films showed semiconductor behavior converted from n-type to p-type conduction after annealing at 450 °C. B-DLC films with a boron content of 5.91 at.% showed a maximum carrier concentration of 1.2 × 1019 cm−3, a mobility of 0.4 cm2/V s, and an electrical resistivity of 1.8 Ω cm. The results of XPS and Raman spectra indicated that the motion of boron atoms was thermally activated during post-annealing, helping promote the formation of C–B bonds in the films. Moreover, the doping of boron in DLC films decreased sp3 bonding and facilitated carbon atoms to form sp2 bonding and graphitization.

Scribing wheel (SW) is an important tool for separating glass panels in thin-film transistor liquid crystal display industry. In this study, unlike the traditional SW completely made of polycrystalline diamond (PCD) or cemented tungsten carbide (c-WC), an alternative partially taking advantage of chemical vapor deposition diamond (CVDD) was newly developed. The fabrication of such unique sandwich-like CVDD-SW combined hot filament chemical vapor deposition (HFCVD), welding, and other machining processes. Both hard CVDD scribing edge and tough c-WC supporting layers contributed to SW structure. CVDD was prepared by adjusting the concentration of methane fed into HFCVD chamber. Morphological observation confirmed the reproducibility of microcrystal diamond (MCD), submicrocrystal diamond (SMCD), and nanocrystal diamond (NCD) diamond. Besides grain size, the existence of columnar structure, the nondiamond carbon content, the residual stress, and I(220)/I(111) ratio of CVDD films were characterized by scanning electron microscopy, Raman spectroscopy, and X-ray diffraction. Based on results, SMCD was predicted as the optimized CVDD for making a scribing edge. After three CVDD films were respectively integrated into SW, this prediction was supported by preliminary scribing test. Selecting Corning-1737 as the cutting object, among three CVDD-SWs and one self-made PCD-SW, only the scribing edge of SMCD-SW kept almost undamaged. The outperformance of our design was thus confirmed.

Diamond disks are indispensable for dressing CMP pads in the manufacture of semiconductors. Conventional diamond disks contain one type of diamond grits, with the aim to achieve two different functions, viz. glaze shaving and asperities grooving. Cocktail diamond disks are made by assembling brazed diamond pallets that contain different types of diamond crystals. Thus, the pad can be dressed clean, and at the same time, asperities may polish wafers fast without damaging.

Due to the continual improvement of CMP technologies, and the need for polishing delicate wafers at high speed, graphite impregnated pads (GiP) dressed by brazed organic dia mond disks (BODD) can double the throughput of wafer-pass at the reduced cost of ownership (CoO). The increased polishing rate is due to the act of nano graphite particles that absorb slurry. The nano graphite particles coated with chemical and abrasive can achieve high removal rate without causing scratches on the wafer. In addition, nano graphite particles do not stick to wafer surfaces, so they can be cleaned easily. BODD can uniquely dress GiP to create slurry channels so the pore free pad is not bottlenecked by slurry supply. This paper also demonstrated the low stress polishing by applying ultrasound during the CMP process.

Sintered polycrystalline diamond cubicles were oriented to make CMP pad conditioners. The dressing experiments demonstrated the capability of fast pad cutting and efficient removal of glazed layer that is formed by polishing wafers with slurry on dressed pad.

In this study, high-temperature stability of nanocrystalline diamond films prepared by hot filament chemical vapor deposition (HFCVD) was investigated through differential thermal analysis/thermal gravimetric analysis (DTA/TGA), thermal analyses, visible and UV Raman analysis, and XPS analysis. Nanocrystalline diamond films with crystalline size of about 25 nm were obtained, which possess high density of grain boundaries with a high sp 2 -bonding of non-diamond carbon. In the initial stage of oxidation, grain boundaries with non-diamond carbon and graphite phase were preferentially etched away by oxygen, which carries on with a faster rate. Then, a slower oxidation rate was continued through reacting the carbon atoms in rigid diamond structure with oxygen. The activation energies for former and the latter, calculated from the thermal analysis, are 195 and 217 kJ/mol, respectively. Both the results of in-situ Raman spectra and XPS spectra indicate that the carbon with sp 2 -bonding significantly decreased with increasing temperature and soaking time.

In this study, high-temperature oxidation of single-crystal diamond and diamond films prepared by hot filament chemical vapor deposition (HF-CVD), were characterized using thermal analysis and high-temperature in-situ Raman analysis. The measurements were performed in various temperatures up to 1300 °C in air and N2 atmospheres. The results indicate that the initial oxidization temperature of diamond film deposited at 700 °C (D700 film) is ≈629 °C, lower than those of diamond film deposited at 900 °C (D900 film, ≈650 °C) and single-crystalline diamond (≈674 °C) in air. Oxidation rate of D700 film at high temperatures appeared to be the highest among the samples studied. A likely cause lies in the fact that, compared to their D900 sample, D700 diamond film contains a larger amount of non-diamond carbon and grain boundaries. However, D900 and D700 diamond films as well as single-crystalline diamond showed no detectable weight loss and oxidization when they were heated up to 1300 °C in N2 atmosphere.

In this research, we demonstrated the viability of oriented AlN layer that incorporated BN to enhance the texturing. Wurtzite (Al, B)N films were deposited on a diamond wafer (diamond film on Si wafer) by a co-sputtering technique. The preferred orientation structure is sensitive to sputtering control factors. The relationship between the microstructures and process conditions were examined with XRD, TEM and AFM analysis. The cross-section TEM images showed that amorphous and randomly aligned structures were produced in the initial sputtering period, but the higher c -axis orientation structure formed as the sputtering time increased. The thickness of the amorphous and randomly aligned layer decreased with increasing sputtering power, nitrogen concentration, substrate temperature and bias voltage. As the thickness of the amorphous and the randomly aligned layer decreased, an (Al,B)N film with higher film quality than AlN was observed.

Current polishing pads cannot polish a workpiece without using slurry with free abrasive. The new slurry is required to be continually poured into the working area, so more than half of the slurry may be lost from the table without contacting the wafer surface; this leads to economic and environmental problems. In the current work, the fixed abrasive pad was used, where nano-sized diamond abrasives were embedded in the polishing pad; distilled water, rather than slurry, was used. The effect of various fixed abrasive pad designs on polishing characteristics during silicon wafer polishing was investigated. Moreover, the primary function of fixed abrasive was to remove the rough parts of silicon wafer as they were being polished. Consequently, it needed to disperse the nano-sized abrasives into the pad material with high hardness value; this way, working abrasives are not pressed into the pad material. Furthermore, with the use of a pad conditioner, the interior working abrasives were exposed to the pad surface. As a result, the best outcome of using the fixed abrasive pad with a nano-sized diamond was a surface roughness of Ra 0.47 nm.

Diamond pad conditioner or dresser can determine the efficiency of chemical mechanical polishing (CMP) processes and the quality of polished wafers. Conventional diamond pad conditioners are made by adhering discrete diamond grits on a flat substrate. The size distribution of diamond grits coupled with the deformation of the substrate often make the tips of diamond grits lying at different heights. Instead of attaching individual diamond grits to a metal substrate, a revolutionary design of pad conditioners is based on carving a structure out of sintered polycrystalline diamond (PCD) matrix. The PCD dresser is manufactured by wire electro discharge machining to form cutting pyramids of a specific size with a designed shape. The dressing characteristics of pad surface textures are studied by comparison with conventional diamond pad conditioner. Experimental results indicate that the PCD dresser can dress asperities of the pad more uniformly than the conventional diamond dresser due to PCD dresser having identically shaped tip and the same height diamond. In addition the cutting rate of PCD dresser for IC1000 pad not only is reduced by about 30% but also it can dress pad more effectively than conventional diamond dresser.

All conventional pad conditioners dress the CMP pad with discrete diamond grits of random orientation. With the advent of polycrystalline diamond (PCD) dressers, the pad conditioning can be performed with an unprecedented regularity. The result is a total elimination of "killer asperities" that may scratch the soft copper layer or porous dielectric layer. Moreover, the PCD dressers may be constructed to form a blade shaver so pad disruption during conditioning can be minimized. As a result, the original pad polymers can be preserved for polishing wafers. This ultimate diamond disk (UDD) has transformed stick slipping pad destruction to smooth shaving pad construction. UDD is particularly suitable for dressing CMP pads for polishing 22 nm interconnects, in particularly, with the anticipated debut of 450 mm pancake wafers scheduled for 2012.

All pad conditioners used for CMP today are made by attaching discrete diamond grits on a flat substrate. Polycrystalline diamond (PCD) was wire-EDM cut to form blades with different designs of cutting tips. These blades were assembled to form the so-called ultimate diamond disk (UDD). The pad asperities formed with UDD were compared with conventional diamond disks. It was confirmed that UDD dressed pad asperities were more uniform than that for polishing IC wafers today. The UDD dressed pads were also used to polish tungsten (W) IC layer deposited on 300 mm wafers. As the surface of PCD contains only merged diamond grains that are corrosion immune, UDD was dressing in-situ, by immersing in the acid slurry. The wafer uniformity so polished was comparable to that of ex-situ CMP pad dressing with metallized diamond disks. The in-situ dressing can boost the CMP throughput by deglazing the pad in real time while the wafer is being polished. After 15 hours, the wafer profiles for this in-situ dressing were sustained without decay.

Diamond-like carbon (DLC) can be lubricious with a frictional coefficient comparable to Teflon (e.g. 0.1). Hydrogen terminated DLC may be more lubricious than pure carbon DLC, but fluorinated DLC can be super lubricious with frictional coefficient less than engine oil (0.01). The fluorinated diamond is actually superhard Teflon that may be named dialon. Dialon is not only virtually frictionless, it is also super hydrophobic, more so than even lotus leaves. In fact, if dialon is coated onto heart valves, it will not accumulate platelets as other artificially made part will do.

When the braze melts, the carbide formers tend to migrate toward diamond to form carbide at the interface. This reaction may be excessive as to degrade diamond’s integrity. In this case, a pre-coating of diamond may be needed to moderate the reactivity between diamond and braze. When diamond is brazed on the surface of a substrate, the melt tends to pull the grits closer together that may thicken the braze layer locally. The clustering of grits can reduce the cutting effectiveness of the diamond tool. A diamond grid design is necessary to maintain the uniform thickness of the braze layer. Moreover, the controlled melting of braze alloy can form a gentle slope around each diamond grit. Such a massive support can allow aggressive cutting of the diamond tool with a low power consumption.

Diamond like carbon (DLC) thin films were used as the cathode layers of inorganic alternating current driven thick dielectric electroluminescent devices. The results indicated that electroluminescent (EL) devices with DLC cathode has superior brightness over the EL with Al or Cr-doped DLC cathodes. Cr-doping in DLC thin film can increase the electrical conductivity, but degrades the EL properties. Also, the EL device with DLC cathode possesses the lowest decay rate among various cathodes, because of the high thermal conductivity and the inert nature of DLC film.

The growth of epitaxial GaN on polycrystalline diamond using highly c-axis orientated AlN as a buffer layer is an attractive application for heat dissipation of LED devices. In this study, the (B,Al)N layer was used to bridge the gap of lattice mismatch between diamond and AlN. For the preparation of (B,Al)N films on a diamond substrate, an aluminum target was sputtered in DC mode and hBN in RF mode simultaneously in a pure nitrogen plasma. The results showed boron content in (B,Al)N film which were determined by X-ray photoelectron spectroscopy (XPS) increased with increase of RF sputtering power. The lattice constant of (B,Al)N films were smaller than pure AlN, suggesting the substitution of smaller boron atoms at Al positions. As the boron content increased, the crystallinity of (B,Al)N films decreased. The crystal qualities of AlN films was analyzed by rocking curve, and AlN was deposited on low boron content (B,Al)N layer with higher c-axis preferential orientation than if it had been grown on diamond directly. © 2007 Elsevier B.V. All rights reserved.

Amorphous diamond can emit electrons in vacuum when applied with an electrical field of only a few volts per micron. It is also extremely thermionic so the emitted current can increase millions times when heated to only a few hundreds degrees centigrade. As a result, amorphous diamond can be a thermal generator or a solar cell. The energy conversion efficiency can have much higher (e.g. 50%) than that (e.g. 15%) of silicon based solar cells that can absorb only a narrow spectrum of sun light. As a solar cell, amorphous diamond has another advantage that its radiation hardness is the highest of all materials, hence, its thermal electricity efficiency will not attenuate as does the solar cell based on photo electric semiconductorls. An immediate application of amorphous diamond is to coat it on electron emitting electrodes, such as that used as cold cathode fluorescence lamps (CCFL) that illuminate liquid crystal displays (LCD) for fornote books and television sets. Amorphous diamond can dramatically reduce the turn-on voltage to lit CCFL so the lamp life can be greatly extended. Moreover, the electrical current can be increased to enhance the brightness of the light.

Diamond grits in tools are typically held in a sintered matrix of metal powder (e.g. Co). The bonding between diamond and the matrix is essentially mechanical. As a result, most diamond grits are easily knocked out from the tool during cutting. The diamond industry has designed various metal coatings (e.g. Ti, Cr, Si) to improve the adherence of diamond grits in the matrix, but the improvements have been modest (e.g. up to 50% increase of tool life). A revolutionary “Active Braze Coated Diamond” (ABCD) is now being developed. The coating of ABCD is much thicker (e.g. 20 microns) than conventional ones (about 1 micron). The molten braze is wetted and reacted with diamond to form strong chemical bond at the interface so that the diamond does not become knocked out of tools. ABCD is coated with a nickel alloy that can form metallurgical diffusion bonds readily with the metal matrix of the tool. In essence, ABCD turns diamond into a metal grain so that the diamond tools can be made by conventional powder metallurgical process without being concerned about the poor bonding between matrix metal powder and the diamond as before.

The fundamental characteristics of dressing action on the polyurethane pad are investigated via dressing by single diamond of different orientations, dressing parameters and dressing path in this study. Experimental results show that a groove with pile-up on both side walls forms as the diamond moves over the pad with a specific dressing depth. The resulting asperities on the pad are strongly affected by the diamond orientation. Plowing is found to be the major mechanism responsible for this surface topology if dressing is conducted by the face of a diamond. On the contrary, cutting action dominates when the point of a diamond is responsible for dressing. It is also found that dressing velocity has an insignificant effect on the groove and ridges created on the pad. The depth of the groove is smaller than the dressing depth due to the spring back of the pad. When the groove created is repeatedly dressed over the same track, the ridge height and groove depth increases for each additional dressing. When two grooves cross each other, the ridges at the four corners of the intersection grow while the depth of the overlapped area decreases. These ridges will become the pressure enhancer of the abrasives to polish the wafer.

Although diamond tools have been used for over a century, the diamond grits distribution in the matrix is not uniform. This is because the large and light diamond grits tend to segregate from the small and heavy metal powder during the mixing process, hence diamond distribution in the diamond tools is intrinsically heterogeneous. As a result, the cutting performance of the diamond tools cannot be optimized. In 1997, Dr. James Chien-Min Sung applied two historical patents that can allow the design of diamond distribution according to a predetermined pattern. As the result, the life of diamond tools may be doubled; and the cutting speed, may also be twice as high. The three-dimensional saw segments with arrayed diamond grits were made back in 1999 with the improved performance as predicted. The Sung invention can allow the diamond tools industry to make ideal saw segment that has variable diamond size and diamond separation at different regions. Conventional diamond saws contain diamond grits that are distributed randomly in a metal matrix, as a result, their cutting speeds are slow and their sawing lives are short. In 1997, Dr. James C. Sung applied new patents that revealed revolutionary technology for making diamond tools with diamond grits set in a predetermined pattern. The diamond placement design was first appeared in a series of DiaGrid® products, such as wire saws and grinding wheels. In 1999, DiaGrid® pad conditioners was introduced and it has since become the world's standard for dressing pads, particularly those used for chemical mechanical planarization of semiconductor devices. In 2005, Shinhan adapted the idea and produced saw segments with diamond grits set in a predetermined pattern, their results confirmed that the sawing speed and the life were significantly improved over conventional designs.

Kinik Company pioneered diamond pad conditioners protected by DLC barrier (DiaShield® Coating) back in 1999 (Sung & Lin, US Patent 6,368,198) and there has been no follower since then. Kinik's offered two varieties of DiaShield® Coatings: ultrahard tetrahedral amorphous carbon and superhard hydrogenated DLC. Kink also evaluated Cermet Composite Coating (CCC or C3, patent pending). C3 is unique that the coating composition grades from a metallic (e.g. stainless steel) under layer to a ceramic (e.g. Al2O3 or SiC) exterior. The metallic under layer can form metallurgical bond with metallic matrix on the diamond pad conditioner. The ceramic exterior is both wear and corrosion resistant. The gradational design of C3 coating will assure its strong adherence to the substrate because there is no weak boundary between coating and substrate. By dipping diamond pad conditioners of various designs in acidic solution (e.g. copper cleaning solution) for extended periods of time (e.g. 50 hours) the chemical inertness of various matrix materials are determined with the decreasing ranking as: hydrogenated DLC > C3 coating > tetrahedral amorphous carbon > sintered nichrome > brazed alloy > electroplated nickel.

Diamond grits synthesized under ultrahigh pressure have been commercially manufactured since 1957. Most of the diamond grits are for sawing rocks (granite, marble) and concrete. In 2004, more than 4 billion carats (800 tons) of diamond saw grits were produced worldwide. About 3/4 of total production was made in China, but the Chinese diamond grits tend to be smaller in size (