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Project manager: Prof. Dr. Wolfgang Maus-Friedrichs, Dr. Lienhard Wegewitz
Funding period: 01/2020 - 12/2022
Funding agency: AiF / IGF
Funding code: 21538 N
Responsible person: N.N.
Development of an optical inspection method for evaluating the surface condition of metal surfaces to be soldered
To date, there has been a lack of fast and cost-effective measurement methods with sufficient reliability for assessing the solderability of component surfaces for close quality control in soldering production. The aim of the project is to use spectroscopic ellipsometry to identify optical properties of metal surfaces that are at least suitable for making reliable statements ("IO" or "non-IO") about the surface condition of these metals with regard to their solderability. For this purpose, the surfaces of materials used in soldering technology (unalloyed and alloyed steels, copper) are modified in a defined manner (oxidized, contaminated with oils, etc.) and their optical behaviour is measured using ellipsometry. At the same time, the adjusted surface conditions are analyzed in terms of materials science and their wetting behavior during soldering is investigated. From this, a correlation is obtained between the set surface conditions, their soldering and wetting behavior and the optical properties of the surface, which allows its solderability to be evaluated solely on the basis of the measured optical properties of the surface. The results should enable the realization of an automatic optical inspection method for component surfaces before (and possibly) after soldering, which could ideally be implemented by means of a very simply constructed ellipsometer suitable for harsh environmental conditions with a measuring range adapted to the material. Especially with regard to SMEs working in contract soldering production, for example, such a measuring method would represent a cost-effective and easy-to-use instrument for improving component quality and minimizing rejects in soldering production.