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.

Additive manufacturing (AM) had a significant influence on the geometry design of products. It became possible to replace the full solid material with cellular structures for the optimal design of AM parts. Various types of cellular structures have been developed and studied for different purposes. However, many studies have focused on an optimal design using cellular structures having near-isotropic properties, such as cube or honeycomb structures. This paper presents the effect of the anisotropic material property on the optimal design by generating cellular structure with anisotropic material property induced by internal void geometry. Kriging metamodel-based material property model is proposed for modeling anisotropy induced by the rotation of internal void. This material model is then applied to the optimal design process. Three types of void geometry, circular, non-rotating, and rotating elliptical void, are considered to demonstrate the effect of anisotropic cellular structure on the optimal design. Due to the anisotropy induced by complex internal void geometry, Kriging metamodel-based material property models are utilized as the material property model. The effect of the anisotropic property and the material property model on the optimized structures is confirmed through two numerical examples in the perspectives of structure performance and density distribution.