Ultrasonic flip-chip bonding method

PROBLEM TO BE SOLVED: To provide a method for ultrasonic flip-chip bonding by which the deformation of a bump can be suppressed by efficiently transmitting ultrasonic vibrations to the joint of the bump and, in addition, a satisfactory bonding strength can be obtained. SOLUTION: In the method for ultrasonic flip-chip bonding, a stress is first applied to the bump without impressing any ultrasonic vibration upon the bump. When a first mean bump stress P1 which is lower than the yield point of the bump as a bulk material is reached, the impression of an ultrasonic vibration having an amplitude A1 is started. After a second mean bump stress P2 which is also lower than the yield point of the bump as the bulk material is reached, the impression of the ultrasonic vibration having the amplitude A1 is performed for a predetermined period of time while the stress P2 is maintained. Then the further increase of the stress applied to the bump is started and, at the same time, the impression of another ultrasonic vibration having an amplitude A2 is started. After a third mean bump stress P3 which is equal to or higher than the yield point of the bump as the bulk material is reached, the impression of the ultrasonic vibration having the amplitude A2 is performed for a predetermined period of time while the stress P3 is maintained. COPYRIGHT: (C)2005,JPO&NCIPI