Thickness evaluation of mesoporous silicon layer using ultrasonic method
Thickness evaluation of mesoporous silicon layer using ultrasonic method
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超声法评价介孔硅层厚度
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
M. Lethiecq
中科院分区：
文献类型：
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作者：
J. Bustillo;J. Fortineau;M. Lethiecq
多孔硅（PoSi）的制造工艺现在允许获得具有可变深度和孔隙率的样品。对于微电子应用，厚度对于确保可靠性是至关重要的。然而，厚度测量方法通常是破坏性的，或者受到厚度或孔隙的强烈限制。因此，在这项研究中，一个非破坏性的超声波方法的基础上浸入插入替代技术进行了研究。然而，超声波方法中的波长比光学方法大得多，允许观察具有更大孔径或更高厚度的多孔硅层。晶片的总厚度（550微米）和纯硅中的高声速（8450 m.s-1）需要具有高中心频率的换能器。这些样品的声学参数，如速度和衰减，使用时域分析测量。这些测量结果进行比较，通过一个一维的多层模型的晶片，使用均匀化的方法为多孔层的基础上毕奥的理论。
The manufacturing processes of porous silicon (PoSi) now allow samples with variable depths and porosities to be obtained. Thickness can be critical to ensure reliability as for microelectronic applications. However, thickness measurement methods are generally destructive or strongly limited by thickness or pore. Therefore in this study a non-destructive ultrasonic method based on an immersion insertion-substitution technique is investigated. Yet wavelength in ultrasonic method is much larger than optical ones, allowing to observe porous silicon layers having larger pore diameter or higher thickness. Total thickness of the wafer (550 microns) and high sound speed in pure silicon (8450 m.s-1) require transducers with high centre frequencies. The acoustic parameters of these samples, such as velocity and attenuation, are measured using time domain analysis. These measurements are compared with those obtained through a one-dimensional multilayer model of the wafer, using a homogenization approach for the porous layer based on Biot’s Theory.