Pages 201-202
In this study, fatigue reliability of halogen free substrate noticed as an environmental harmony type printed circuit board backing was evaluated. And, the examination was demonstratively carried out on the difference of the failure mechanism in fatigue breakdown and static destruction from the mesoscopic viewpoint. (1) There was a difference in both fatigue life, though mechanical property of the halogen free material was almost equal to it of the halogen material. That is to say, the fatigue life of the halogen free material was longer than the halogen material. (2) In the halogen free material, the crack was comparatively generated in initial stage in the fatigue life. In the meantime, in the halogen material, it immediately came to the rupture, when the crack was generated, and it was frailly destroyed. (3) From the fractographic study, it was indicated that the difference in fatigue life of the halogen free material and fatigue life of the halogen material was controlled by the difference of size (Unit Fracture Area) of the characteristic destruction pattern.
