This paper presents a preliminary study about effects of ultrasonic vibration on machined surface and subsurface damages in rotary ultrasonic machining (RUM). The surface and subswface damages are compared for machining of dental ceramics (AI2O3) with and without ultrasonic vibration. The surface chippings are evaluated and the subsurface cracks are observed under scanning electron microscope (SEM).
Chemical Mechanical Polishing (CMP) is a major manufacturing step extensively used to planarize semiconductor wafers. In CMP, the polishing pad surface is glazed by residues. A diamond disc conditioner is used to dress the pad to regenerate new pad profile and asperity in order to maintain favorable process conditions. This paper presents a review on process modeling of diamond disc pad conditioning in CMP. Following the introduction, the paper briefly introduces a technical background of the conditioning process and process control. It then summarizes research work on the various analytical process models proposed and ends with conclusions and topics for future research.
Chemical mechanical polishing (CMP) is used to remove irregularities on the silicon wafer surface. The importance of CMP is the achievement of both local and global planarity of wafer surface. This paper presents an economic study on CMP of silicon wafers. A cost model is developed to predict the total cost for CMP of silicon wafers. An input-output model is developed to analyze parameters relevant to the fixed cost and variable cost. The labor cost is investigated through a flow chart of the labor operation. Based on the cost model, a hypothetical case study is conducted to show the model’s capability of performing sensitivity analysis and identifying critical factors for the total cost for strategic management purposes.
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