Bump joining method

A bump-joining apparatus for joining bumps formed at an electronic component to electrode portions on a circuit board, which comprises:

• a vibration generation device for vibrating the bumps of the electronic component having the bumps faced to the electrode portions and the electrode portions relatively for the joining;
• a pressing device for moving the electronic component and the circuit board relatively in a direction to bring the bumps and the electrode portions close to each other, and pressing the bumps of the electronic component and the electrode portions to each other, so as to compress the bumps;
• and
• a control unit for controlling the vibration generation device and the pressing device in operation, which executes a pressing action control to the pressing device to change a contact-area corresponding to each of the bumps to each of the electrode portions through the compressing from an initial contact area corresponding to each of the bumps to join-completed-contact area corresponding to each of the bumps at the completion of the joining which exceeds the initial contact area, and a vibration control to the vibration generation device to generate constant vibration from a time when the contact-area reaches the initial contact area to a time when the contact-area reaches the join-completed-contact area.