UltraScale+ Device Packaging and Pinouts Product Specification User Guide (UG575)

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1.19 English

Solder paste is applied to PCB metal pads by screen printing. The volume of the printed solder paste is determined by the stencil aperture and the stencil thickness. In most cases, the thickness of a stencil must be matched to the needs of all components on the PCB. Stencil apertures should be a circular shape. To ensure a uniform and high-solder paste transfer to the PCB, laser-cut stencil, made from mostly stainless steel, is typically used. Nickel Blank stencils, referring to stencils where the entire foil is laser-cut from a sheet of pure nickel material, can also be used. However, high-quality nano-coated stencils (laser cut from stainless steel) can perform as well as or better than Nickel Blanks.