An oxygen-free atmosphere is created using vacuum chambers and high-purity nitrogen. In the first step, the vacuum is applied to 1 mbar absolute pressure and the chamber is then refilled with N2. The O2 content is diluted by a factor of 1000. This results in an oxygen content of 200 ppm with 20% atmospheric oxygen. If the process is repeated, the O2 content in the chamber is <1ppm. The oxygen-free atmosphere is often required during soldering in order to achieve good wetting of the solder materials on the joining partners. In flux-free soldering with hydrogen or formic acid, O2 contamination leads to dewetting of the liquid solder and thus to defects in the joint.