Diamond Pad Research Articles

The In-Situ Dressing of CMP Pad Conditioners with Novel Coating Protection

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.

Amorphous Diamond Dresser for CMP Fixed Abrasives Pad

The primary consumables in chemical mechanical polishing (CMP) are the polishing pad and slurry. The polishing pad significantly influences the stability of the polishing process and the cost of consumables (CoC). Usually a diamond pad conditioner is used to scrap off the polishing debris from the pad top. Recently, an alternative planarization process can be achieved by polishing with a "fixed abrasive pad" (FAP). In order to dress bumps on FAP, this paper use an amorphous diamond, a diamond-like carbon deposited by cathode arc system as the dresser for FAP. The amorphous diamond can produce a surface relief that ranges from a few nanometers to about 200 nanometers. With the addition of this dressing step on a rotary platform, FAP can renew its polishing surface 10 to 100 times before the bumps are used up. The pad cost for polishing can be reduced by at least ten folds and make FAP more desirable than slurry pad for silicon wafer manufacturer due to its intrinsic capabilities to produce flatter wafers with high polishing rate.

ATLAS diamond Beam Condition Monitor

The ATLAS experiment has chosen to use diamond for its Beam Condition Monitor (BCM) given its radiation hardness, low capacitance and short charge collection time. In addition, due to low leakage current diamonds do not require cooling. The ATLAS Beam Condition Monitoring system is based on single beam bunch crossing measurements rather than integrating the accumulated particle flux. Its fast electronics will allow separation of LHC collisions from background events such as beam gas interactions or beam accidents. There will be two stations placed symmetrically about the interaction point along the beam axis at z = ± 183.8 cm . Timing of signals from the two stations will provide almost ideal separation of beam–beam interactions and background events. The ATLAS BCM module consists of diamond pad detectors of 1 cm 2 area and 500 μ m thickness coupled to a two-stage RF current amplifier. The production of the final detector modules is almost done. A S / N ratio of 10:1 has been achieved with minimum ionizing particles (MIPs) in the test beam setup at KEK. Results from the test beams and bench measurements are presented.

Development of a Pad Conditioning Method for Oxide Film CMP using a High Pressure Micro Jet (HPMJ)

The goal of this study is to determine if a High Pressure Micro Jet (HPMJ) conditioning system can be used as substitute for, or in conjunction with, conventional diamond pad conditioning Oxide film inter layer dielectrics (ILD) of fifty wafers were polished successively to compare HPMJ conditioning with diamond conditioning. The characteristics of pad conditioning were evaluated by removal rate (RR), coefficient of friction (COF), Pad flattening ratio (PFR), scanning electron microscope (SEM) images, and pad roughness (Ra). Results indicate that HPMJ was able to clean the pad surface, but it did not provide enough energy to abrade the surface of the pad. Based on this a new pad conditioning method, which is a combination of diamond and HPMJ conditioning has been proposed. This combined method allows for stable polish results, but also can reduce micro scratches and defects caused by abrasives on the pad or the pad itself.

Nitrogen-doped diamond films selected-area deposition by the plasma-enhanced chemical vapor deposition process

Abstract The nitrogen-doped diamond films have been successfully synthesized by using urea as the nitrogen source. Selected-area deposition of diamond nuclei was formed by using a SiO 2 layer as the masking material. Diamond pads, around 9 μm in diameter, were obtained when the N-doped diamond films were deposited on these patterned diamond nuclei using the chemical vapor deposition process. An emission current density as high as 200 μA/cm 2 , with a turn-on field of around 8 V/μm, was obtained. However, the diamond emitters broke down easily, which is ascribed to the localized melting of the substrate materials surrounding the diamond pads.

Properties of electron field emitters prepared by selected area deposition of CVD diamond carbon films

Selected area depositions (SAD) of diamond films were successfully achieved on silicon by two different approaches. In the first case, a standard lift-off technique employing a patterned SiO2 layer was used as a mask, and in the second case commercial ink-jet printer technology was adapted to be used to seed diamond nano-grit onto silicon. Patterned, boron-doped diamond pads roughly 5.6 μm in diameter were formed by CVD growth on patterned SiO2/Si substrates and found to be composed of closely packed carbon clusters approximately 250–800 nm in size each containing 50-nm particles embedded in them. The patterned diamond film seeded by ink-jet printing formed after CVD growth with in situ boron-doping, dots (85 μm in diameter) containing poly-crystals in the nanometre range. The resulting patterned diamond films were characterised by Raman and scanning electron microscope (SEM) analysis and then configured as cold cathode field emitters to determine their electron emission performance. The results suggest that patterned diamond films produced by ink-jet printing offer a simpler method for fabricating planar diamond emitter arrays with field emission and conduction properties which could be tailored to improve the performance and fabrication cost of cold field emitters in state-of-the-art field emission displays.

Effect of polishing on cyclic fatigue strength of CAD/CAM ceramics.

The biaxial flexural strength and cyclic fatigue biaxial flexural strength of CAD/CAM ceramics polished with #220, 400, 600 and 1000 diamond pads were measured in an effort to determine the effect of surface roughness on fatigue behavior of dental ceramics. The surface roughness was improved after polishing with a smaller diamond grain pad. The flexural strengths of the specimens polished with #220, 400, 600 and 1000 diamond pad were 75.2, 76.6, 82.2, and 83.3 MPa, respectively; the fatigue flexural strength of those with #220, 400, 600 and 1000 were 53.0, 58.1, 60.0, and 61.5 MPa, respectively. Both the flexural and fatigue flexural strengths increased with improvement of surface profile. These results suggest the importance of polishing of dental ceramics for not only the static strength but also the cyclic fatigue strength.