Process yield is an important criterion used in the manufacturing industry for measuring process performance. In this paper, we study the lower confidence bound and capability testing for true process yield which is estimated by the estimator of Spk with the presence of measurement errors. The results indicate that the presence of measurement errors in the data leads to different behaviors of the estimator according to the entity of the error variability. It can be used to determine whether manufacturing processes meet the capability requirement when the measurement errors occur. A real example from a semiconductor manufacturing process was used to demonstrate the proposed methodology.