| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a joining material comprising stacked solder materials simultaneously satisfying two characteristics of the joining characteristic actualizing joining at low temperature such as that of an Sn-based alloy and the stress relaxation characteristic actualizing absorption of mechanical stress caused by difference in the coefficient of thermal expansion between a semi-conductor chip and a package such as that of a Pb-based alloy. Ž<P>SOLUTION: Hoop-shaped joining materials having the width substantially equal to that of a hoop-shaped stress relaxation material made of Pb or a Pb-based alloy, thinner than the hoop-shaped stress relaxation material, and having the melting point lower than that of the stress relaxation material are superposed on both sides of the stress relaxation material. Both materials are positioned by one or more horizontal guide roll and one or more vertical guide roll, and supplied, are supplied and subjected to cold pressure welding (and finish rolling) with a draft being ≥50% to obtain the stacked solder materials having the thickness of the stress relaxation layer being ≥50 μm and the thickness of the joined layer being ≥20 μm. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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