Method of forming dice and structure of die

A method of forming dice includes the following steps. First, a wafer structure is provides, which includes a substrate and a stack of semiconductor layers disposed in die regions and a scribe line region. Then, the substrate and the stack of the semiconductor layers in the scribe line region are removed to form a groove in the substrate. After the formation of the groove, the substrate is further thinned to obtain the substrate with a reduced thickness. Finally, a separation process is performed on the substrate with the reduced thickness.