Optimization of Substrate Sizes for In Situ Stress Measurement in Electrodeposits Relying on Nonlinear Effects

Abstract

In situ stress measurements have been widely used in various deposition processes for stress detection. The substrate size can affect the uniformity of curvature across the entire surface, which is a major cause of incorrect stress measurements. However, because of the inherent concept of measurement theory and the complexities of the influence of substrate size on measurement accuracy, the underlying nonlinear effects of the rectangular substrate are still not fully understood. We discovered that increasing the substrate size caused an increase in nonlinear effect (nonuniform distribution of curvature radii and stresses in the x and y directions) and surface defects on the rectangular substrate using in situ stress measurement. Furthermore, the bending stiffness of the substrate, which was influenced by the substrate size, was established to illustrate the effect of substrate size on the nonlinear effect. The total stress of the deposit was concentrated at the edge in both the x and y directions, and the deposit at the edge was prone to delamination and cracking. When the substrate size was reduced, the deposit surface did not show obvious defects, and the stress errors in the x and y directions were only 2.34% and 2.54%, respectively. These findings will be beneficial to improve the accuracy of in situ stress measurement and further understand the causes of nonlinear effects.