PROCESS CONTROL FOR UMG-SI MATERIAL PURIFICATION

摘要

A process control method for UMG-Si purification by performing a directional solidification of molten UMG-Si to form a silicon ingot is described. The ingot is divided into bricks and the resistivity profile of each silicon brick is mapped. A crop line for removing the impurities concentrated and captured in the ingot during the directional solidification is calculated based on the resistivity map. The concentrated impurities are then removed by cropping each brick along that brick's calculated crop line.