Pad printing - a novel thick-film technique of fine-line printing for solar cells

The purpose of this work was to study the suitability of pad printing (tampon printing) -an innovative gravure offset (indirect) printing technique. Pad printing offers the possibility of a simple, economic and high through-put manufacture of fine-line metallization below 50 µm on solar cells lowering the optical losses caused by the grid. Only with pad printing is it possible to print fine-line grids on irregular surfaces of ribbon silicon. Pad printing is much more softer to the wafers than screen printing - we never observed solar cell breakage of fragile materials. The printed wafers were fired in a rapid thermal processing furnace. The resistivity and the contact resistivity were measured by a test structure. First not yet optimized solar cells were produced. The results were comparable to those produced by conventional thick-film techniques.