Basic Study on the high-Temperature Deformation in Thin Metallic Films and Wires

金属薄膜和线材高温变形的基础研究

基本信息

批准号：
10650688
负责人：
ITOH Goroh
金额：
$ 2.3万
依托单位：
Ibaraki University (2000)Nagaoka University of Technology (1998-1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

To elucidate the difference in the deformation and fracture mechanisms between connect lines in microelectronic circuits and bulk materials, effects of specimen thickness, t, and grain size, d, on the high-temperature creep deformation behavior in Al-1%Si-0.5%Cu alloy thin sheets and foils have been investigated. The alloy is frequently used for connect lines in the form of sputtered thin film line. The primary issue of this study is whether the high-temperature deformation mechanism of simply thin aluminum materials is different from that of the bulk material or not, and whether the same type of fracture as in what is called stress induced voiding takes place in such thin materials or not.The results showed that steady-state creep rate was proportional to the -α-th power of t/d, and that the exponent α was approximately constant and unity at the applied stress σ of 30 MPa and over. The value of α decreased with decreasing the applied stress but was always positive in the range of the … More present experimental condition. This means that the creep rate increases with increasing grain size and with decreasing specimen thickness. Although apparent stress exponent was a value as high as from 7.9 to 10.4, taking the threshold stress into account, true stress exponent was deduced to be 5. The result that the dispersion of silicon phase particles was observed supports the existence of threshold stress, and the true stress exponent of 5 (dislocation creep controlled by recovery or dislocation climb ) was supported by the TEM observation that the microstructure during the steady-state creep consists of subgrains. Fractograpy showed that intergranular fracture as was observed in the case of stress induced voiding did not occur. The fracture morphology was dimple-forming type in the near-bulk specimens where t≧200μm, and chisel-line type, typical to the extremely ductile materials, in thinner specimens where t≦100μm. From these results, it has been deduced that high-temperature deformation in such thin materials proceeds in a newly proposed model based on heterogeneity in the subgrain structure during the deformation, where subgrains are finer in the vicinity of the grain boundary and coarser near the free surface. This model is expected to become one of the fundamental theories in the field of high- temperature deformation in metallic materials where merely homogeneous microstructure has been taken into account so far. Less

为了阐明微电子电路和块状材料中连接线之间的变形和断裂机制的差异，以及样品厚度 t 和晶粒尺寸 d 对 Al-1%Si-0.5% 中高温蠕变变形行为的影响对铜合金薄片和箔进行了研究，该合金经常用于溅射薄膜线路的连接线，本研究的首要问题是其高温变形机制是否简单。薄铝材料是否与块体材料不同，以及在这种薄材料中是否发生与所谓的应力诱导空洞相同类型的断裂。结果表明，稳态蠕变速率与t/d 的 -α 次方，并且在施加应力 σ 为 30 MPa 及以上时，指数 α 近似恒定且一致。α 值随着施加应力的减小而减小，但在范围内始终为正值。目前的实验条件是这样的。蠕变速率随着晶粒尺寸的增加和试样厚度的减小而增加，尽管表观应力指数高达 7.9 至 10.4，但考虑到阈值应力，推导出真实应力指数为 5。观察到的硅相颗粒支持了阈值应力的存在，并且稳态蠕变期间的微观结构的TEM观察支持了真实应力指数5（由恢复或位错爬升控制的位错蠕变）断口形貌显示，在t≥200μm的近块体试样中，没有发生应力诱导空洞时观察到的沿晶断裂，断口形态为凿线型。具有极延展性的材料，在t≤100μm的较薄样品中，从这些结果可以推断出在如此薄的情况下的高温变形。材料在基于变形过程中亚晶结构的异质性的新提出的模型中进行，其中亚晶在晶界附近较细，在自由表面附近较粗，该模型预计将成为该领域的基本理论之一。迄今为止，仅考虑均匀微观结构的金属材料的高温变形研究较少。