| 摘要 |
PROBLEM TO BE SOLVED: To prevent faulty insulation due to migration generated by moisture or water between small pitch electrode pads mounting a flip chip or the like on a wiring board. SOLUTION: Generation of faulty insulation due to migration can be prevented by a method wherein the wiring substrate having annular patterns 3 consisting of a second metal having a migration sensibility lower than that of a first metal and surrounding the electrode pads 2 made of the metal 1 and being insulated electrically from the second metal is prepared. When the first metal is silver or a silver alloy and the second metal is gold, gold/silver alloy containing 75% or more of gold, palladium or palladium/silver alloy containing 50% or more of palladium, the first and second metals become more effective and, further, when the pattern width of the annular patterns 3 is specified to be larger than 2μm, stabilized effect can be obtained for a long period of time. COPYRIGHT: (C)2003,JPO
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