Papers by Keyword: CMP

Abstract: Studying the surface characteristics of polishing pad helps to understand and analyze the chemical mechanical polishing (CMP) mechanism and optimize the microscopic structure of polishing pad. The surface roughness, organizational structure, porosity, depth and diameter of micro-pore, distribution of asperity and profile bearing rate of IC1000/Suba IV polishing pad were studied with the profilometer ZYGO 5022, AFM and SEM. The results of measurement and calculation show that the surface roughness is 6.8μm , the root mean square ( RMS ) roughness is 9.4μm, the surface porosity is 56 % , the micro-pore average diameter is 36μm , the micro-pore average depth is 20μm , the micro-pore average spacing is 43μm , the micro-pore average volume is 550/mm2 and the asperity height obeys Gaussian distribution.

Abstract: The polishing pad’s wear influences the surface accuracy of the polished wafer. A new polishing pad wear model is established using the idea of Finite Element Analysis (FEA) and the effect of polishing parameters on the wear of polishing pad is discussed.

Abstract: The abrasive ice disc chemical mechanical polishing (AID-CMP) is a potential polishing process in the semiconductor industry to realize superior surface finish and planarity for semiconductor wafers. In this paper we investigated the temperature field during GaAs wafer AID-CMP process for a better understanding of AID-CMP. The results show that the AID outer temperature is higher than the inner, and the highest temperature in AID is at the wafer/AID contact zone. The increases of Pc, v, eh and tp will generate more energy and cause more local melting during GaAs wafer AID-CMP process. The AID temperature and the area of highest temperature zone increase with increasing Pc, v, and eh. The nodes temperature increase in every conditions adopted as tp increases. The area of melted zone and thickness of melted ice increase with increasing Pc, v, eh and tp.

Abstract: In order to increase the material removal rate of silicon wafer, composite abrasives slurry was used in CMP. The mechanism of interaction between silica abrasives and polymer particles was analyzed. Small silica abrasives were seen to attach onto the surface of the polymer particles. Composite abrasives slurry was obtained by adding polymer particles into single abrasive slurry. Three key parameters, the concentration of colloidal silica, the concentration of polymer particle and the speed of polishing, which influence the material removal rate of silicon wafer were analyzed by Taguchi method and the optimal parameters were obtained. Experimental results indicated that the maximum material removed rate of 353nm/min was obtained when optimal craft parameters of 5% colloidal silica, 3% polymer particle, 50rpm plate and carrier rotation speed were selected.

Abstract: The effect of slurry composition and wafer flatness on a material removal rate (MRR) and resulting surface roughness which are evaluation parameters to determine the CMP characteristics of the on-axis 6H-SiC substrate were systematically investigated. 10 x 10 mm2 6H-SiC substrates and 2-inch SiC wafers fabricated from the ingot grown by a conventional physical vapor transport (PVT) method are used for this study. The SiC substrate after the CMP process using slurry added oxidizers into slurry consisted of KOH-based colloidal silica and nano-size diamond particle exhibited the significant MRR value and a fine surface without any surface damages. SiC wafers having high bow value after the CMP process exhibited large variation in surface roughness value compared to wafer with low bow value. The CMP-processed SiC wafer having a low bow value of 10m was observed to result in the MRR value of 0.15 m/h and the mean height (Ra) value of 0.772Ǻ.

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: 2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.

Abstract: In this article, the correlation of surface morphological defects and barrier-height inhomogeneities with the electrical characteristics of defective 4H-SiC Schottky barrier diodes (SBDs) before and after chemical-mechanical polishing (CMP) is investigated. The forward characteristics, an ideality factor and a single barrier height of a SBD, remain the same after CMP, so that CMP does not affect SBD characteristics. Most barrier-height inhomogeneities are eliminated or improved after CMP. Therefore, leakage current induced by barrier-height inhomogeneities are improved by CMP as well. In addition, about 40% of SBDs with carrots inside the active areas exhibits double barriers before CMP. This excludes that carrots are a cause of barrier-height inhomogeneities. In reverse-bias mode, CMP reduces reverse leakage current at low bias and increases breakdown voltage due to the reduction of thermionic field emission and elimination of local enhanced electric fields.

Abstract: Although various diamond polishing techniques have been studied for many years, no individual method can polish free-standing CVD diamond film with high efficiency and high polishing quality. This paper investigates polishing CVD diamond film by the combination of electro-discharge machining (EDM) and chemical mechanical polishing (CMP). Scanning electro microscopy, Optical microscopy, Energy dispersive X-ray analysis, Talysurf surface profiler and Raman spectroscopy were used to evaluate the surface integrity and quality of diamond film before and after polishing. Based on the experimental results, the material removal during EDM process can be a chemo-mechanical process, including gasification, melting, sputtering, oxidation and graphitization. While in CMP process, diamond was removed under the mechanical and tribochemical interaction. The combination of EDM and CMP has advantages of high efficiency, high polishing quality and low damage. It is suitable to polish large area free-standing CVD diamond film.

Abstract: This study analyzed immediate implantation and immediate loading of chemical mechanical polished (CMP) and resorbable blast media (RBM) SSIII OSSTEM dental implants histometrically. The 1st, 2nd, 3rd, and 4th mandibular premolars were extracted from five adult dogs. Immediate implantation was performed in the fresh extraction sockets. Each dog received two types of implant: CMP and RBM. The first premolar was submerged, whereas the second, third, and fourth were not submerged. The implants were splinted using acrylic resin and subjected to immediate loading. After 4 months, X-rays were taken and analyzed. The animals were euthanized and processed histologically to obtain non-decalcified sections. Longitudinal ground sections of each implant were made, and histometry was analyzed under light microscopy. No significant difference was found between the control and experimental groups based on immediate loading (p > 0.05) and implant surface (p > 0.05). The implant survival rate and implant-to-bone contact rate after immediate loading were similar to those of submerged implants. The CMP and RBM dental implants did not differ in terms of implant survival rate and implant-to-bone contact rate.