Patent ID: 7475803

Claim:
A method for forming solder bumps on connection pads of a printed wiring board, the method comprising: providing a solder ball loading unit comprising a loading device having a suction portion and an opening portion, the loading device being configured to move over a surface of a ball arranging mask having openings corresponding to connection pads of a printed wiring board, the suction portion and opening portion of the loading device being configured to gather solder balls into a group inside the opening portion with negative pressure provided by the suction portion on a portion of the surface of the ball arranging mask surrounded by the opening portion; positioning the loading device over a portion of the ball arranging mask; sucking air from the suction portion such that the solder balls are gathered into the group inside the opening portion with negative pressure on the surface of the ball arranging mask; and moving the loading device horizontally with respect to the surface of the ball arranging mask such that the group of solder balls gathered inside the opening portion on the surface of the ball arranging mask is moved on the surface of the ball arranging mask and a solder ball in the group drops through one of the openings of the ball arranging mask onto a respective one of the connection pads of the printed wiring board.