• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.48-54
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• 2012

In recent years, developments in the semiconductor and electronic industries have brought a rapid increase in the use of large size silicon. However, for many companies, it is hard to produce 400mm or 450mm wafers, because of excesive funds for exchange the equipments. Therefore, it is necessary to investigate 300mm wafer to obtain a better efficiency and a good property rate. Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This research investigated the surface characteristics that apply variable machining conditions and Taguchi Method was used to obtain more flexible and optimal condition. In this study, the machining conditions have head speed, oscillation speed and polishing time. By using optimum condition, it achieves a ultra precision mirror like surface.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.1-6
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• 2008

In recent years, developments in the semiconductor and electronic industries have brought a rapid increase in the use of large size silicon wafer. For further improvement of the ultra precision surface and flatness of Si wafer necessary to high density ULSI, it is known that polishing is very important. However, most of these investigation was experiment less than 300mm diameter. Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study reports the machining variables that has major influence on the characteristic of wafer polishing. It was adapted to polishing pressure, machining speed, and the slurry mix ratio, the optimum condition is selected by ultra precision wafer polishing using load cell and infrared temperature sensor. The optimum machining condition is selected a result data that use a pressure and table speed data. By using optimum condition, it achieves a ultra precision mirror like surface.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.310-317
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• 2013

In this paper, the contact pressure of the wafer and polishing pad for final polishing process for 300 mm-wafer were investigated through numerical analysis using FEM tool, ANSYS. The distribution of the contact pressure is one of main parameters which affects on the flatness and surface roughness of polished wafers. Two types of polishing head, a hard type head with ceramic disk and a soft type head with air bag were considered. The effects of the deformation and initial shape of table on the contact pressure were also examined. Both heads and tables were modeled as 3D finite element model from solid model, and the material properties of polishing pads and rubber plate for the air-bag head were obtained from tensile tests. The contact pressure deviation on wafer surface was smaller with air bag head than hard type head even when the table had form errors such as convex or concave. From this 3D analysis, it could be concluded that the air-bag head has better uniformity of the contact pressure on wafer. Also, the effects of inner diameter of air bag and radial clearance between wafer and retainer were investigated as view point of contact pressure concentration on the edge of wafer.