1、 112 COMPUTATIONAL METHODS IN ENGINEERING AND SCIENCE EPMESC X Aug 21 23 2006 Sanya Hainan China 2006 Tsinghua University Press total stress intensity factors caused by vapor pressure in penny shaped crack K ic delamination toughness measured by delamination test at 240 C In case of the system B and
2、 system C connected by the ACF B and ACF C respectively the values of delamination toughness for all jointed interfaces are higher than the total stress intensity factors caused by the vapor pressure during reflow process So the system B and system C are expected not to be delaminated If we assume t
3、hat the system B has a penny shaped crack with the radius of 120 m at the interface between the ACF and the Al pattern the total stress intensity factor due to the vapor pressure are almost the same as the delamination toughness of an interface crack between the ACF and the Al pattern Therefore we c
4、ould presume that disconnected flip chips of the system B shown in Table 4 have a delamination or void equivalent to a penny shaped crack with the radius of 120 m at the interface 124 between the ACF and the Al pattern Similarly we could presume that the system C has a penny shaped crack with the ra
5、dius of 100 m at the interface between the ACF and a substrate Conclusively the occurrence of the delamination of ACF in a flip chip during solder reflow process after moisture absorption can be estimated by comparing the delamination toughness with the stress intensity factor caused by the vapor pr
6、essure CONCLUDING REMARKS We dealt with the reliability studies of electronic packaging that is the strength evaluation of plastic packages during solder reflow process and the delamination evaluation of anisotropic conductive adhesive films during solder reflow process In both studies computational
7、 mechanic approaches can be applied as a powerful tool for obtaining moisture concentration in the resin and the stress intensity factors of a V notch and an interface crack It can be concluded that computational mechanics approaches are key technologies for the reliability studies of electronic pac
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9、nterfacial crack J Appl Mech 1988 55 98 103 4 Ikeda T Miyazaki N Soda T Mixed mode fracture criterion of interface crack between dissimilar materials Eng Fract Mech 1998 59 725 735 5 Miyazaki N Ikeda T Soda T Munakata T Stress intensity factor analysis of interface crack using boundary element method Application of virtual crack extension method JSME Int J 1993 36 36 42 6 Kassir MK Bregman AM The stress intensity factors for penny shaped crack between two dissimilar materials J Appl Mech 1972 39 308 310
