METHOD OF MANUFACTURING CIRCUIT BOARD TO WHICH ELECTRONIC COMPONENT IS JOINED

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method in which reliability of a circuit board to which an electronic component is soldered can be improved or a method of forming a solder bump.SOLUTION: This invention relates to a method of manufacturing a circuit board to which an electronic component is joined including the following steps (a)-(e) of: (a) arranging a solder transfer sheet on a first surface having a soldering part of a circuit board so that a solder layer of the transfer sheet is opposed to the first surface; (b) selectively causing solid-phase diffusion junction between the soldering part of the circuit board and the solder layer of the transfer sheet by heating the circuit board on which the transfer sheet is arranged at the temperature lower than the solidus temperature of solder alloy under pressure; (c) obtaining the circuit board in which the solder layer is bonded to the soldering part by separating the transfer sheet and the circuit board; (d) cleaning the circuit board with a cleaning agent A; and (e) melting the solder layer by heating the circuit board at the temperature higher than the liquidus temperature of the solder alloy after applying flux to the circuit board, solidifying the solder and cleaning flux residue.