This study introduces a novel retainer ring design aimed at mitigating the edge effect during chemical mechanical planarization. The innovative design features an arch-shaped geometry that creates a bending effect, thereby reducing excessive pressure on the wafer's edge. A two-dimensional axisymmetric finite element model was developed, and simulation data were utilized to create a metamodel. Multi-objective optimization was conducted using an evolutionary algorithm, focusing on the normal contact stress on the wafer surface. Representative Pareto-optimal designs were analyzed to assess the distribution of normal contact stresses. The results demonstrated that the proposed design significantly reduced peak normal stresses and enhanced stress uniformity, especially at the wafer edge. This optimized retainer ring is anticipated to improve wafer edge quality and increase semiconductor yield.

Factors such as weight reduction and improved fuel efficiency of vehicles interfere with the efficiency of roller bearings in automobiles under harsh conditions. In particular, studies are ongoing to increase the load capacity and rigidity under highspeed conditions. The development of tapered roller bearings that can be used under high-speed conditions is accelerating. In the case of high-speed bearings, factors such as centrifugal force, gyroscopic moment, and slippage have a greater influence on the performance of the bearing, unlike the traditional operating mechanisms. The resulting lubrication characteristics have a profound impact on the failure mode of the bearing. In particular, unlike traditional roller bearings, system failure due to damage to the retainer frequently occurs, suggesting the need for prompt investigation. In this study, the rotational characteristics and strength of three models, a steel cage and two plastic cages for tapered roller bearings with the same internal structure, were examined. A comparative analysis of retainers with different shapes and materials can reveal the factors contributing to optimal performance under high-speed operating conditions and the optimal design of bearings.