A computer model and methodology to predict temperatures and deformations during diamond multi-wire cutting

Abstract

Analysis of structured wire wafering processes to predict optimized process settings by varying particle size and wire diameter AIP Conference Proceedings 1999, 140001 (2018) Abstract. The Diamond wire slicing process for multi-Si wafering is relatively new, and there are limited threedimensional 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.

Grain flash temperatures in diamond wire sawing of silicon

“…While it was shown that the coolant has a significant effect on the wafer temperature field [12], temperatures in the contact zone are typically much higher than the boiling temperature and therefore have little effect on the temperature in the cutting zone [13]. Lindholm et al [14] have studied the coolant temperature rise during wire sawing of multi-crystalline silicon and have simulated the temperature change during the cut along with the resulting effects of thermal expansion. Depending on the cooling conditions, the heat generation between the wires and the silicon block has been determined to lie between 0.28 and 0.43 W/mm, leading to temperatures in the material of up to 270 • C in the beginning of the cut.…”