Thin film solder paste deposition method and tools

Abstract

Solder is deposited on chip elements or other potentially irregular surfaces by applying solder paste to a thin porous sheet such as cotton twill cloth so that the solder paste fills open areas therein. The solder volume is thus regulated by the texture and structure of the porous sheet. The porous sheet is then placed in compression against the surface to which solder is to be applied and the solder in the solder paste reflowed in an oven, preferably including a nitrogen atmosphere. At the same time, excess flux is absorbed by the porous sheet to facilitate subsequent cleaning while the reflow of solder is accurately and repeatably controlled. The process and resulting structure are particularly appropriate to the manufacture of discrete electronic devices which include an array of chip components such as capacitor chips sandwiched between plate structures. The process and structure also provides highly repeatable, high quality solder connections between curved surfaces.

Dependencies are inferred from the claim text.