A Computer Model and Methodology to Predict Temperatures and Deformations during Diamond Multi-Wire Cutting

The Diamond wire slicing process for multi-Si wafering is relatively new, and there are limited three-dimensional thermal field simulations in this area. This work aims to fill the gap by using a Finite-Element model to simulate this complex mechanical-thermal process where the wires and wafers are continuously working in a thermally expanded region of the block. The non-uniform three-dimensional temperature field generated in the block leads to uneven contraction and deformation of wafers, which may impact on wafer strength. This process is not well understood. The model accounts for important slicing parameters such as cooling fluid flow rate, temperature difference, block length and wafer thickness in real production environment. It predicts a three-dimensional thermal field, and also quantifies wafer expansion/contraction at different places in a block. The obtained results can potentially help to optimize slicing recipe for better wafer strength and morphology, and to produce high quality wafers for solar panels.