The method includes disposing semiconductor chips on a package substrate having sawing lines, forming an encapsulant to cover the semiconductor chips on the package substrate, forming a package assembly by a first curing of the encapsulant, forming first grooves by cutting the encapsulant along the sawing lines, performing a second curing of the encapsulant, and dividing the package assembly into unit semiconductor packages by cutting the package substrate along the sawing lines and forming second grooves to overlap the first grooves.