A New Double Exponentially Weighted Moving Average Run-to-Run Control Using a Disturbance-Accumulating Strategy for Mixed-Product Mode

Mixed-product production is common practice in semiconductor manufacturing and has attracted considerable academic attention recently. The main purpose of the mixed-product mode is to manufacture a wide variety of products in the same time period, to meet customer demand. The complex and changeable group of products is called 'mixed-product production mode.' A specific tool used and a specific product manufactured are together called a 'thread.' There is a need for 'threaded' Run-to-Run (RtR) control in semiconductor manufacturing. This article develops a new product-based, disturbance-accumulating strategy in threaded RtR control by means of the double exponentially weighted moving average (dEWMA) technique. The main idea is to develop two disturbance-accumulating strategies; one for the intercept update of the same product between cycles and the other for the disturbance update in terms of the previous product between cycles, cope with the transient and transition effects, respectively. A comprehensive simulation study is conducted to compare the performance of the proposed product-based RtR controller with the existing controls specifically designed for the mixed-product mode. The proposed control has great promise as an extremely competitive threaded RtR controller in practice. Note to Practitioners - Run-to-run (RtR) control has been widely applied in batch manufacturing processes to reduce variation and has been identified as a turn-key technology for maintaining quality outputs in semiconductor manufacturing. The mixed-product production mode poses a great challenge of how to adjust process recipes between different products to alleviate initial recipe bias, process shifts, and patterned disturbances from run to run, product to product, and cycle to cycle. The proposed mixed-product RtR controller is developed based on a novel disturbance-accumulating, product-based strategy. This new controller is easy to implement in practice and has been shown to be effective in producing high-quality control outputs.