Transport and surface treatment of semiconductor materials - uses moving belts inside modular treatment chambers with movements which optimise the process to reduce contamination and cost

摘要

The treatment of polycrystalline semiconductor grade material, including etching, cleaning and drying, is carried out inside reaction chambers, pref. hermetically closed by a lid and contg. an exhaust, where the material is moved about using continuous belts. The chambers are pref. modules which can be used singly or in combinations. The material is constantly being moved to expose all surfaces to the media, and can be passed through multiple reaction chambers. Pref. chamber media are baths of mineral acids or acid mixts., caustic solns. or mixts. of these, organic bases or mixts. of these or watery rinsing solns.. Also claimed is the use of heating by radiation, convection or microwave energy. The belts used are pref. a type of link-belt or a perforated plastic belt, using a non-contaminating material, e.g., Si or PVC, polypropylene, polyethylene or polyvinylidenefluoride. The transport belts are pref. inclined under an angle of 0-50 deg.. USE/ADVANTAGE - The avoidance of metal in transport reduces the contamination of the pieces of semiconductor material with conventional tool and container materials, e.g., Fe, reducing the amt. of material that needs to be etched off in cleaning. The absence of crushing stages reduces the prodn. of fine grained material. This reduces the transfer of liq. reaction chamber treatment medium from one chamber to the next and so reduces the cross contamination and material usage with consequent further cost redn.. The process is used in the mfr. of Si semiconductor material for use in crystal growing reactors.