Slicing parameter optimization based on wire net dynamic reliability constraint in multi-wire saw

Abstract

Multi-wire sawing technology has become the mainstream method to slice crystalline silicon for solar cells and integrated circuits due to its processing efficiency, high yield, and easy adaption to the trend of large diameters. However, wire breakage due to unreasonable process parameters can cause heavy losses during slicing. The complexity of the slicing process and lack of theoretical guidance are the root causes. To solve these problems, a wire net dynamic reliability assessment method based on reliability theory is established based on a Weibull distribution and wire net series discrete model. The forces on the wire in the slicing process are analyzed to obtain the resultant force of the dynamic process. Experiments are conducted, and the influence of tension, wire bow angle, speed, acceleration, and contact length on wire net dynamic reliability is analyzed. The results show that the factors affecting wire net dynamic reliability are, in descending order of importance, wire bow angle, wire tension, wire net maximum wear loss, contact length, wire acceleration and wire speed. The wire net dynamic reliability varies exponentially with the bow angle and tension. Values less than 2.5° and 16 N, respectively, have a minor influence on the wire net dynamic reliability. However, when these are more than 4.5° and 20 N, the wire net dynamic reliability decreases dramatically. In the ranges of the two thresholds, the wire net dynamic reliability decreases slowly with the increase of the wire bow angle and tension. The other two parameters, wire speed and acceleration, have similar trend with wire net dynamic reliability. But their impact is not significant within the usual parameter ranges. Wire net maximum wear loss is importent parameter for the reliability. With the increase of wire net maximum wear loss, the wire net dynamic reliability decreases approximately linearly. On the contrary, wire net dynamic reliability increases linearly with the increase of contact length. The establishment of the model provides a theoretical basis for the reasonable determination of process parameters and the prevention of wire breakage.