Stencil Print Applications and Progress for Crystalline Silicon Solar Cells

This paper describes laboratory testing to research the capabilities of stencil printing, as compared to screen printing, with a focus on fine line high aspect ratio printing on crystalline silicon wafer material. Scanning of potential of screen and stencil printing moving to finer fingers shows advantages for stencil printing. Testing of electroformed, laser cut, single and double layer stencils, and using various pastes, demonstrates the need for improved paste rheology. Optimal line definition with an aspect ratio of 0.37 was obtained with single layer stencils with fully open fingers. In a two step process, with a stencil for only fingers, followed by screen print of the busbars, +0.4% efficiency gain was reached for industrial type mc-Si cells.