36 巻 (2018) 1 号 p. 16-20
Bondability of thermosonic flip chip bonding using ramp bond force profile was investigated. Compared with a conventional method using constant bond force profile, ramp bond force profile achieved higher bond strengths with same amount of bump deformation. This was because that expansion amount of contact area between bump and electrode under applying ultrasonic vibration increased. Furthermore, we found out that pressure in bonding process at interface between bump and electrode of ramp bond force profile became lower than constant bond force profile. Bondability was considered to have been improved by incrementation of slip between bump and electrode cause by lower pressure.