Thin film batteries (TFB) are fabricated by a process which eliminates and/or minimizes the use of shadow masks. A selective laser ablation process, where the laser patterning process removes a layer or stack of layers while leaving layer(s) below intact, is used to meet certain or all of the patterning requirements. For die patterning from the substrate side, where the laser beam passes through the substrate before reaching the deposited layers, a die patterning assistance layer, such as an amorphous silicon layer or a microcrystalline silicon layer, may be used to achieve thermal stress mismatch induced laser ablation, which greatly reduces the laser energy required to remove material.