Micro-interface formation control of electronic devises based on analysis of solid state bonding mechanism

为了理解粘接的基本原理，在超高真空条件下对粘接行为进行了观察。采用Al、Au、Cu、Ni细丝作为电路线，Au、Al、Cu、Ni箔作为电子焊盘。真空度为1×10^-8；pa。在粘合之前，它们的表面通过Ar离子轰击进行了清洁。俄歇分析发现，Ar离子清洗前的表面有一层氧化膜，而Ar离子清洗后表面的氧化膜被去除。在Au-Au键合中，与Au-Ni和Au-Cu键合一样，键合区的形成是从接触区的中心产生的。然而，如果使用铝丝，则外围区域首先键合，而中心区域不易键合。为了弄清这一现象，对粘接后的粘接行为进行了研究，并对粘接后的粘接行为进行了俄歇分析。结果表明，即使在超高真空条件下，经过Ar离子清洗几十分钟后，铝的表面也会受到氧的作用，形成一层很薄的氧化膜，这对粘附性的形成有很大的影响。这是控制固相结合过程的一项非常重要的知识。也就是说，在铝线与焊盘的键合过程中，铝线与焊盘接触的侧面的折叠现象是增加铝线与焊盘的强结合面积所必需的。结合这一思想，较好地控制了Al-Au-Ar、Al-Al、Al-Si键合界面的形成过程，并利用激光多普勒振动仪测量了键合工具的摩擦系数，获得了良好的界面形成条件。研究结果在2005年3月的研讨会上进行了报告，并做出了最终报告。

The adhesion behavior was observed under an ultra-high vacuum condition in order to comprehend the fundamental bonding principle. Al, Au, Cu and Ni fine wires were used as circuit wires and also Au, Al, Cu and Ni foils were used as a electronic pad. The vacuum degree was 1x10^<-8> Pa. Their surfaces were made clean by Ar ion bomberdment before bonding. It was found that the surfaces before Ar ion cleaing has an oxide film but the oide film is removed by Ar ion cleaning based on Auger analysis. In Au-Au bonding, the bonded area formation is produced from center of contacted area as like as Au-Ni and Au-Cu bonding. However, if Al wire is used, the periphery area was firstly bonded and the center area is not easily bonded. In order to make this phenominon to be clear, the adhesion formation behavior was investigated and Auger analysis was carried out after bonding. As a result, it was suggested that the surface of Al was attacted by oxygen and a very thin layer oxide film was formed several ten miniutes after Ar ion cleaning even under the ultra-high vacuum condition and the film had a large influence on the adhesion formation. This is an very important knowledge to control the solid state adhesion process. That is, the folding phenomenon of side surface of Al wire contacted to the pad is necessary for increasing the strong bonded area during the the bonding of Al wire to the pad. Taking this idea into consideration, the interface formation process of Al-Au ar Al-Al, Al-Si bondings was controlled well and also the good formation condition was obtained by measuring the vabration of the bonding tool using leaser Dopplar vibriometer. The results were reported in Symposium of Mate2005 and the final report was made.