“Which New Stencil Technologies Provide the Best Paste Printing Performance?”

ABSTRACT The implementation of new component technologies such as 01005 components, 0.4mm & 0.3mm pitch CSPs and QFNs will drive the stencil technology to improve the solder paste release for these very small solder pads. These new assembly technologies will require the implementation of stencils that provide solder paste release for area ratios at 0.5 and lower. To date, Electroformed Ni stencils have shown that they can improve the solder paste release below 0.66 Area Ratios and down to 0.5. But there are a few concerns surrounding Electroform stencils, such as: Highest cost, dimensional accuracy and stencil thickness variation across the stencil. A number of new Stencil Technologies have been introduced in the last couple years, such as New Pulse Lasers, Fine Grain SS, Laser cut Ni foil & Nano-coated stencils. BUT which of these new stencil technologies perform the best for solder paste release for very low Area Ratios? This paper will evaluate the following stencil technologies: 2 types of Fine Grain SS alloys cut with Pulse lasers 2 types of Fine Grain SS alloy cut with Pulse lasers & Nano-coating Fine Grain SS alloy cut w/ Pulse lasers & Electroless Ni plating Electroform Ni foil blank cut with Pulse laser Electroform Ni grown stencils The goal of this study is to determine which of these new stencil technologies will provide the best choice in order to implement the new component technologies that will require Area Ratios below 0.5. For this experiment, we will only utilize a 4 mil thick stencil.