The Bonding Forming Simulation And Reliability Research Of The Flip Chip Stacked Gold Stud Bump

Flip chip technology is one of the main chip connections. The stacked gold stud bump bonding forming and the stress and the strain of the stacked gold stud bump is researched in this paper used the method which combine the finite element simulation with the experiment, and the result show: the larger stress locate the edge of a concentric circles which center lie the geometric center of the pad, the bonding will form preferred in this area; the stacked gold stud bump height should decreased when the bonding pressure, bonding time and bonding power increases with the time, the first gold stud bump diameter and the second gold stud bump diameter should increase when the bonding pressure, bonding time and bonding power increases with the time. The capillary has more influence to the key size of the second gold stud bump compare to the first gold stud bump, so it is necessary to set bonding parameter of the bonding pressure and the bonding power reasonable in second gold stud bump bonding, in order to ensure the second gold stud bump working normal.The stacked gold stud bump stress and strain research in the conditions of cyclic thermal loading and that research based on the orthogonal experimental design with bonding parameters in different levels, and the result show:the distribution about the thermal cycle stress and strain of the stacked gold stud bump is not uniform, the maximum strain and stress appear in the area of the bonding surface shout the bump and the pad; The range analysis and the variance analysis of the key maximum stress and strain bout the stacked gold stud bump under the thermal cycles load show: the bonding pressure have largest influence to the stress and the strain of the gold stud bump, the bonding power take second place, and the bonding time have smallest influence to the stress and the strain of the gold stud bump;The bonding pressure has a significant effect to the double gold stud bump, and the remaining bonding parameters are not significant. the optimal level of bonding parameter about the stacked gold stud bump is that : the bonding pressure is 64 gf, the bonding power is 0.15 w and the bonding time is 34 ms.Some samples about the stacked gold stud bump have a thermal cycling load reliability experiment with 100 days a total of 2400 hours, and the range analysis and variance analysis of the failure data show that: he bonding pressure have largest influence to the stress and the strain of the gold stud bump, the bonding power take second place, and the bonding time have smallest influence to the stress and the strain of the gold stud bump;The bonding pressure has a significant effect to the double gold stud bump, and the remaining bonding parameters are not significant. the optimal level of bonding parameter about double gold stud bump is that : the bonding pressure is 64 gf, the bonding power is 0.15 w and the bonding time is 34 ms. Under the thermal cycle loading, the scale parameter h and shape parameter b of Weibull distribution about the double gold stud bump are respectively 515.1522 and 5.032403; the life expectancy(life expectancy) E(t) is 474.3985 hours; the median life 0.5t is 478.967 hours; the characteristic life 0.368 t is 515.1186 hours.