International Journal of Abrasive Technology (4 papers in press)

• Estimation of dressing effects in chemical-mechanical polishing with sorts of diamond dressers
  by Kuen-Ren Chen, Hong-Tsu Young 
  Abstract: To achieve global planarization, chemical mechanical polishing (CMP) is used in the semiconductor manufacturing process. To maintain the stability and the throughput of CMP, the polishing pad needs to be dressed by a diamond dresser. By calculating the distribution of the scratch numbers of diamond grit in the pad, the effect of dressing can be estimated and the pad profile can be predicted. Different types of dressers, including ring-type and full-type, different pitches and arrangements are used in CMP process. The diamond pitch is relative to the number of diamonds and the scale of the total scratch time, but does not affect the profile of the scratch time. Regular or random arrangement makes no difference in the profile of the scratch times. The width of the ring influences the number of diamonds and the scale of the total counts although the profiles remain similar.
  Keywords: Chemical Mechanical Polishing; Diamond Dresser; Dressing; Trajectory Analysis
   
• A study on the equilibrium condition of the oxide layer in ELID grinding
  by Indraneel Biswas, A Senthil Kumar, Mustafizur Rahman 
  Abstract: Grinding with Electrolytic In-Process Dressing (ELID) is gaining popularity for machining hard and brittle materials due to its excellent surface generation capabilities. However, till date no fundamental investigation on the formation and erosion of the oxide layer deposited on the wheel has been conducted. In this study, ELID grinding experiments are conducted and it is found that the electrolytic current attains a steady value. The dressing current is controlled by the oxide layer thickness, which in turn, is determined by its formation during electrolytic dressing and erosion during grinding. When these formation and erosion rates reach equilibrium, a steady layer thickness is achieved, producing steady current. The phenomenon is theoretically investigated by formulating electrolytic dressing to find oxide formation per wheel rotation. Oxide erosion, per wheel rotation, during grinding is formulated and the solution of these formulations for successive wheel rotations gives the change in dressing current with grinding time. The theoretical results show that a constant current value is achieved due to equilibrium of oxide formation and erosion rates, and these are substantiated by experimental findings.
  Keywords: ELID grinding; superabrasive; metal bond; dressing current; electrolytic dressing;
   
• Mirror surface finishing of acrylic resin using MCF-based polishing liquid
  by Yongbo Wu, Takashi Sato, Weimin Lin, Keita Yamamoto, Kunio Shimada 
  Abstract: This paper deals with the experimental investigation on the detailed performance of MCF (magnetic compound fluid)-based polishing liquid (MPL) in nano-precision surface treatment of acrylic resin that is essentially required for producing the model in the process of developing an inaugural mechanical system. The MPL is produced in practice by mixing iron powder, abrasive particle and -cellulose fiber into a MF (magnetic fluid), and hence a kind of functional fluid reacting to magnetic fields. Following the previous works confirming the performance of MPL in the surface finishing of acrylic resin, in this work a series of experiments were conducted to reveal how the process parameters affect the machining characteristics in details in order to establish the new technique. The results showed that a mirror surface can be easily obtained once the process parameters have been set up optimally.
  Keywords: MCF; acrylic resin; surface treatment; polishing; surface roughness; material removal
   
• PCD dresser for dressing CMP polyurethane pads
  by M. Y. Tsai, James C. Sung 
  Abstract: This paper investigated 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% and also it can dress pad more effectively than conventional diamond dresser.
  Keywords: Chemical mechanical polishing; Polishing pad; Diamond conditioner