| 摘要 |
PURPOSE:To significantly lower the occurrence of exfoliation at point A under high temperature standing test by adding specific quantity of one or two kinds of No and W to produce Pd having purity higher than a specific value containing inevitable impurities thereby improving the sphericity and the high temperature bonding strength of ball within a specific compositional range. CONSTITUTION:One or two kinds of No and W are added by 10-500 atomic ppm to produce Pd having purity higher than 99.9% containing inevitable impurities. Consequently, diffusion of base metal layer is suppressed at the time of thermocompression. At the time of ball formation, a part of the additive elements Mo, W produce oxides MoO and WO which evapolate from the ball surface at a low melting point thus producing a right spherical ball. When the elements are added less than 10 atomic ppm, diffusion of the base metal layer cannot be sufficiently suppressed although the sphericity of ball can be achieved and thereby occurrence of exfoliation at point A can not be lowered. |
