Patent ID: 8592256

Claim:
A circuit board manufacturing method applied to a semiconductor device that is manufactured by impregnating a fiber base material with a resin to manufacture a circuit board with a thickness of not more than 500 μm, mounting a semiconductor element on the circuit board, encapsulating at least an upper portion and side faces of the mounted semiconductor element using an encapsulation resin composition, carrying out post mold curing processing for heating and curing the encapsulation resin composition, and carrying out reflow processing for attaching solder balls to a surface of the circuit board opposite to a surface thereof with the semiconductor element mounted thereon using a reflow device, characterized by comprising: a heating step of heating the circuit board using the reflow device at a higher temperature than a glass transition temperature of a cured product of the resin with which the fiber base material is impregnated, before mounting the semiconductor element on the circuit board.