DUAL INDEPENDENT TRANSPORT SYSTEMS FOR IR CONVEYOR FURNACES AND METHODS OF FIRING THIN WORK PIECES

摘要

Multi-lane, side-by-side, independently driven transport systems particularly useful for transfer, on conveyor belts or finger/chains, of thin work pieces, such as silicon wafers, through processing equipment for converting the wafers into solar cells, including UV pre-treaters, dopers, dryers, diffusion furnaces and metallization furnaces. The inventive multi-lane transport systems may employ wire mesh belts having a flying bridge wafer support system comprising longitudinally spaced carrier wire elements that support the wafers at their side edges at only point contacts, by means of opposed, inwardly inclined, downwardly slanted segments or wings. Alternately, finger drives comprising spaced-apart chains having inwardly projecting fingers may be used for transport of the wafers by side edge contact. Friction or sprocket drives having tensioner assemblies associated therewith are used to move the transport belts or finger chains through the furnace zones. Each lane may be independently controlled to provide unique thermal profiles along their processing paths.