At present, local mechanical properties can be measured not only for macroscopic objects but also for nano-objects and thin films with dimensions of only a few tens of nanometers. For these purposes, special indentation devices can be used. In past decades, many special data measurement and processing methods for thin film characterization have been developed. In addition, the method is no longer restricted to materials science but now also has a wide range of applications for biological problems in which the hardness/modulus values are quite different from those in materials science for which the method was originally designed. Data interpretation in the field of metrology is not so straightforward and care is required in dealing with quantitative results, especially if dealing with very soft samples. Therefore, it is necessary to use reference samples that would enable the comparison of different instruments and the validation of the applied methods. In this contribution, we present the results of our effort on preparing and testing thin film-based reference materials prepared using plasma technologies. We describe a deposition procedure that allows us to produce samples with a large range of hardness and modulus values. From these, we choose a very soft but stable sample that is then further tested to verify its suitability as a reference sample. The major issues discussed in this article are the repeatability of the deposition process, time stability, and homogeneity.