[en] We improved the critical current properties of fluorine-free metal organic decomposition processed YBCO thin films prepared on buffered metallic substrates by increasing the thickness of the films. YBCO films prepared using a conventional one-time growth exhibit a maximum I _c (77 K, ∼0 T) value of ∼100 A per 1 cm width for a film with a thickness of 0.8 μm, and I _c decreases with further increases in the film thickness due to the generation of impurity particles and micro-cracks. In this study, a multiple growth process was adopted for the preparation of thick films to avoid these problems. The I _c of films prepared using this method monotonically increased with the film thickness. YBCO films with a thickness of ∼3.0 μm recorded a quite high I _c (77 K, ∼0 T) value for ∼210 A cm⁻¹ width. Additionally, the in-field J _cs at 20 K and 40 K were found to increase almost proportionally to the film thickness. (paper)