Investigations of strength properties of ultra-thin silicon
Investigations of strength properties of ultra-thin silicon
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超薄硅的强度特性研究
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
C. Landesberger
中科院分区：
文献类型：
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作者：
S. Schonfelder;J. Bagdahn;M. Ebert;M. Petzold;K. Bock;C. Landesberger
薄硅为微电子和微机械行业提供了多种新的可能性，例如用于 3D 集成（堆叠骰子）或光电元件 (LED)。薄晶圆通过研磨、抛光或蚀刻等背面减薄技术制造，并切成单芯片。分离技术可以与背面减薄技术（减薄切割）相结合，以提高芯片的可靠性和强度。为了在质量和制造良率方面表征和优化相关工艺步骤，还必须研究缺陷形成和强度方面的机械性能。本文通过三点弯曲测试对三种不同的切割技术进行了表征。第一种技术是普通锯切工艺。第二种和第三种技术是“减薄切割”工艺，一种采用锯切凹槽，另一种采用干法蚀刻沟槽。除了实验研究之外，还进行了分析和数值计算，以了解力和位移的非线性关系，并根据断裂力计算断裂应力。通过威布尔理论对结果进行统计评估。使用这种方法可以更全面地了解工艺对强度性能的影响，而与几何因素无关。特别是，它为预测通过实际设备测试确定的强度以及通过使用改进的技术（例如减薄切割）来量化强度增加的潜力奠定了基础。本文表明，力与位移的非线性关系是可以描述和解释的。因此，可以计算所有测试样品的断裂应力作为强度参数。通过“减薄切割”分离的样品比简单锯切的样品具有更高的强度。如果通过干法蚀刻工艺制作沟槽，则强度可以大大增加。
Thin silicon offers a variety of new possibilities in microelectronical and micromechanical industries, e.g. for 3D-integration (stacked dice) or optoelectronic components (LED). The thin wafers are fabricated by back thinning technologies like grinding, polishing or etching and diced into single chips. The separation technologies can be coupled with back thinning technologies (dicing-by-thinning) to increase the reliability and strength of dies. In order to characterize and optimize relevant process steps in terms of quality and fabrication yield, also the mechanical properties have to be investigated with respect to defect formation and strength. In this paper three different dicing technologies were characterized by 3-point bending tests. The first technology is a common sawing process. The second and third technology are "dicing-by-thinning" processes, one with sawn grooves and the other with dry-etched trenches. In addition to the experimental investigations, analytical and numerical calculations were performed in order to understand the nonlinear relationship of force and displacement and to calculate fracture stresses from fracture forces. The results were statistical evaluated by the Weibull theory. Using this approach allows a more comprehensive understanding of the influence of the process on strength properties independently of geometric factors. In particular, it forms a base to predict the strength determined from tests for real devices and to quantify the potential of strength increase by using improved technologies, such as Dicing-by-Thinning. It was shown in this paper, that the nonlinear relationship of force and displacement can be described and explained. Thus the fracture stress as parameter of strength could be calculated for all tested samples. Samples, being separated by "dicing-by-thinning", have much higher strength than simply sawed samples. If trenches are made by dry-etched process the strength can be increased tremendously.