Semiconductor devices with flexible reinforcement structure

Methods for manufacturing semiconductor devices having a flexible reinforcement structure, and associated systems and devices, are disclosed herein. In one embodiment, a method of manufacturing a semiconductor device includes electrically coupling at least one semiconductor die to a redistribution structure on a first carrier. The semiconductor die can include a first surface connected to the redistribution structure and a second surface spaced apart from the redistribution structure. The method also includes reducing a thickness of the semiconductor die to no more than 10 μm. The method further includes coupling a flexible reinforcement structure to the second surface of the at least one semiconductor die.