3D Electroform Stencils for Two Level PCB

摘要

The requirements for two-level PCB with components on both levels have seen a recent increase. Stencil printing on both levels requires special stencil and squeegee blade designs. This poster paper will examine two such requirements. The first requirement is printing solder paste for .3um uBGA with pads on two levels of the PCB separated by 7 mils (175um) height. The second requirement is for printing flux or solder paste into a recessed cavity on the PCB for placement of an embedded flip chip. The cavity depth is 14 mils (350um). 3D Electroform stencils will be used for both of these print requirements. Rubber squeegee blades, metal squeegee blades, slit metal squeegee blades, and notched metal squeegee blades will be tested. Print results including paste volume and paste volume dispersion as well as pictures of the solder bricks and flux deposits will be presented in this poster paper.