INFLUENCE OF BALL-FORMING CONDITIONS ON THE HARDNESS OF COPPER BALLS

被引：20

作者：

ONUKI, J

KOIZUMI, M

SUZUKI, H

ARAKI, I

IIZUKA, T

机构：

[1] HITACHI LTD,TAKASAKI WORKS,TAKASAKI,JAPAN

[2] HITACHI CABLE LTD,DENSEN WORKS,HITACHI,JAPAN

来源：

JOURNAL OF APPLIED PHYSICS | 1990年 / 68卷 / 11期

关键词：

D O I：

10.1063/1.346972

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Effect of ball-forming conditions on the microstructure and the hardness of balls has been investigated in order to obtain soft balls suitable for a reliable ball-bonding process using copper wire. Copper balls formed in a room-temperature shield gas are found to be harder by 6 Hv than fully annealed copper wires of the same purity. This is caused by many dislocation loops which are generated in balls due to inclusion of gaseous impurities from the atmosphere and due to rapid solidification. On the other hand, copper balls formed in a shield gas heated above 175 °C are found to be softer by the amount of 4.5 Hv than balls formed in a room-temperature shield gas. This is due to disappearance of dislocation loops caused by the reduction of solidification rate and by elimination of gaseous impurities from the balls during solidification. Impurities, especially oxygen, are found to have a strong influence on the hardening of copper balls. From these results, we conclude that copper balls formed in a shield gas heated at 175 °C are suitable for mass production.

引用

页码：5610 / 5614

页数：5

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