Methods of forming semiconductor devices include thinning a region of a semiconductor wafer and forming at least one semiconductor die laterally within a thinned region of the wafer. One or more reinforcement structures may be defined on the wafer. Semiconductor wafers include one or more reinforcement structures that extend laterally along the wafer and project from at least one surface of the wafer. The wafers further include a plurality of at least partially formed semiconductor dice laterally within at least one region having a thickness that is less than a thickness of the reinforcement structures. The wafers may include a plurality of at least partially formed semiconductor dice laterally within each of a plurality of thin regions defined between a plurality of reinforcement structures. The thin regions may have an average thickness less than an average thickness of the reinforcement structures.