Development of Technique of Creation of Small-Scale Crack and its Application to Micro Strength Test

近年来，机械工程学对这一现象的研究已经深入到微观领域。在断裂力学领域，对小尺寸裂纹和缺陷的详细分析变得越来越重要，传统的处理方法是将其视为完全小的。此外，如果使用显著的半导体工艺技术的进步，也有可能产生这样一种形状高度可控的小尺寸缺陷，因此被认为有可能不是被动地而是主动地制造裂纹几何形状。本研究的目的是建立高精度的小尺度裂纹断裂力学实验方法。具体地说，我们研究了利用半导体工艺技术制造小尺寸裂纹的方法，以及评估引入的小尺寸裂纹引起的退化的测量技术。研究…单晶产生小裂纹的各种方法在硅胶含量较高的情况下，研究表明，采用电感耦合等离子体刻蚀和Ta作为掩模材料的组合性能最好。它能够产生宽度为20μμ，深度为45μμ的小规模裂缝。利用制成的试件进行了小载荷下的三点弯曲试验，并对试件的弯曲强度进行了研究。结果表明，小裂纹的引入使强度降低了约230 Mpa。用有限元方法进行了应力分析，应力集中系数约为5，由此推测产生的缝隙底部的最大应力约为902 Mpa，超过了无缝隙的硅试件的抗弯强度*00 Mpa。在威布尔概率纸上画出了强度的分布，在直线上画出了数据，显示了材料的脆性，符合预期。对于没有缝隙的试件，使用从概率纸中估计的威布尔参数来执行尺度效应。预计有缝隙试件的强度将会下降，因为缝隙底部的面积比没有缝隙的试件的切割面积小。然而，强度的下降不能仅用尺度效应来解释，因此可以认为存在一些特定于微观结构的效应。这些问题都没有得到解决。较少

In recent years, the phenomenon treated by the mechanical engineering has reached the micro domain. In the field of fracture mechanics, the detailed analysis of the small-scale crack and the defect conventionally dealt with as if it was fully small has increased importance. Moreover, if progress of remarkable semiconductor process technology is used, it is also possible creating such a small-scale defect with highly controlled shape and so it is considered to become possible to make crack geometry, not passively but actively. The purpose of this research is the establishment of experimental method of fracture mechanics using the small-scale crack with high accuracy. Specifically, we investigated the manufacturing method of small-scale cracks using the semiconductor process technology together with the measurement technique of the evaluation of degradation resulting from the introduced small-scale crack. Examining various methods for creation of small-scale cracks on the single crystal … More silicone, it was shown that the combination of ICP etching and the Ta as the mask material shows the best performance. It was enabled to create a small-scale crack with 20μμ width and 45μμ depth. Three points bending test under small load was conducted using the manufactured specimen and the bending strength was investigated. The results showed that the strength decreases by about 230MPa by introduction of small-scale cracks. The stress analysis was conducted using finite element method and the stress concentration factor was shown to be about 5 and thus the maximum stress at the bottom of the created slit is supposed to be about 902MPa which exceeds the bending strength *00MPa for silicon specimen without slit. The distribution of the strength was plotted on the Weibull probability paper and the data were plotted on the straight line which shows the brittle property of the material as was expected. Scale effect was performed using Weibull parameters evaluated from the probability paper for the specimen without a slit. It was expected that the strength of specimen with slit will decrease since the area of the bottom part of the slit is smaller than the cut area of the specimen without slit. However, the decrease of strength could not be explained only by the scale effect and so it is supposed that the some effects that is specific to the micro-structure exist. These are left unsolved. Less