An elemental stacked Mo/Sn/Cu/Zn/Se precursor was prepared by sputtering pure elemental targets of Sn, Cu, and Zn sequentially onto Mo-coated glass substrates, followed by thermal evaporation of Se. To compensate for typical Sn loss observed during the thermal annealing of precursors in a tube-type rapid thermal annealing reactor, a custom-designed quartz/Se/Sn cover was added to the sample tray. It was found that Sn was supplied in the form of a binary compound, SnSe x , and thus, the delamination of Cu 2 ZnSnSe 4 (CZTSe) from the Mo layer was well suppressed. It was also found that an increase in the Se layer thickness (1, 3, and 5 μm) in the precursor structure could result in more severe delamination of CZTSe from the Mo layer and an increase in the Sn thickness (300–500 nm) in the quartz/Se/Sn cover could lead to the incorporation of more Sn and Se into the CZTSe structure.