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本文制作了微焊点试件,并通过施加较大的电载荷使其发生了电迁移。对微焊点在电迁移过程中的微观组织形貌及其演化进行了观察。结果发现,高温和常温条件下的电致失效模式都是阴极处的界面断裂,但是低温条件下的迁移试件会在阳极处形成凸丘,而高温下则没有。此外,本文还测试了微焊点在电迁移过程中的电阻、温度场以及塑性变形,以期找到微焊点电致损伤的表征方法。实验表明,红外方法可以快速准确地发现焊点表面和内部的缺陷,而电阻值对微焊点的电致损伤并不敏感。最后本文采用有限元方法分析了微焊点的电致应力及空位浓度,较好地解释了微焊点电致失效的机制。
In this paper, a micro-solder test piece was fabricated and electromigrated by applying a large electric load. The micro-morphology and evolution of micro-spots during electromigration were observed. It was found that both the high-temperature and normal-temperature modes of electrical failure were interfacial fractures at the cathode, but the migratory specimens at low temperature formed convex hills at the anode and not at high temperatures. In addition, we also tested the resistance, temperature field and plastic deformation of the micro-welding spot during the electromigration, in order to find out the characterization of the micro-spot electrical damage. Experiments show that the infrared method can quickly and accurately find the solder joint surface and internal defects, and the resistance of the micro-solder joint electrical damage is not sensitive. Finally, the finite element method is used to analyze the electrosensitive stress and vacancy concentration of the micro-welding spot, and the mechanism of the electrical failure of the micro-welding spot is well explained.