METHOD AND APPARATUS FOR MAKING AN ELECTRICAL DEVICE

摘要

The invention relates to a method and apparatus to use nitrogen, or any other inert gas, or a reducing gas as a process gas to reflow and planarize solder paste (14) in a single heating step. The inert gas may also be used to cool the solder paste (14) after reflowing. According to one method soldered paste (14) is printed onto the printed circuit board (10) with conventional methods employing a mask or stencil (16). A mesh, die, or mold element (20) having a plurality of openings therein is lowered onto the soldered paste (14) and the printed circuit board (10) is reflowed and planarized in a single heating step. Once the paste (14) is applied, the parts are reflowed and planarized in a single, brief, thermal excursion. The heated mesh (20) is lowered into the solder paste (14) causing the paste (14) to wick through the mesh (20) forming a meniscus. A hot gas knife is arranged to plane the meniscus of the solder paste (14) off of the mesh (20). An inert, nitrogen, or reducing gas is diffused through the knife to prevent oxidation.