| 摘要 |
PURPOSE:To obtain the gold alloy thin wire for bonding having high fracture strength and heat resistance and having drastically reduced vibration fracture rate by adding specified amounts of Y, Ca and Ag to high purity gold. CONSTITUTION:By weight, 3 to 100ppm Y, 1 to 50ppm Ca as well as 4 to 110ppm Y+Ca and furthermore 5 to 100ppm Ag are added to high purity gold. As the above high purity gold, the one contg. gold of about >=99.99wt.% purity and the balance inevitable impurities is preferably used. The above addition of Y and Ca gives strains to the crystal lattices of gold to increase the recrystallization temp. and to precipitate Y and Ca into the grain boundaries, by which the strength at an ordinary temp. and heat resistance can be improved. Furthermore, the addition of Ag suppresses the precipitation of Y and Ca into the grain boundaries to improve the toughness. In this way, the gold alloy thin wire in which mechanical characteristics at an ordinary temp., loop height, ball shape, etc., are suitably maintainable and having low vibration fracture rate can be obtd. |
