Thickness measurement of polymer thin films with high frequency ultrasonic transducers
Thickness measurement of polymer thin films with high frequency ultrasonic transducers
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DOI：
10.1063/1.5099765
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
Richard J. Smith;S. Cavera;F. Pérez-Cota;L. Marques;M. Clark
中科院分区：
文献类型：
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作者：
Richard J. Smith;S. Cavera;F. Pérez-Cota;L. Marques;M. Clark
在本文中，我们提出了一种表征聚合物薄膜厚度的方法，更有趣的是，描述了聚合物薄膜(1微米)的厚度变化。该技术在聚合物膜上使用光声换能器；当换能器的声波在聚合物层内共振时，我们能够光学监测波的干涉，其模式是局部聚合物厚度的特征。光声模型被用来模拟换能器共振和聚合物腔模式的干扰，允许与实验进行比较，以便对样品区域内每个位置的聚合物腔长度进行反向工程。这种方法得到的厚度图与实验声频的变化非常相似，并且在10×10 mm的大样品上显示了≈200-500 nm的厚度梯度。通过利用千兆赫频率的超声波，这项技术提供了获取聚合物薄膜纳米特性的途径，并可应用于聚合物科学领域的薄膜厚度监测应用。在本文中，我们提出了一种表征聚合物薄膜厚度的方法，更有趣的是，它可以表征聚合物薄膜(1微米)的厚度变化。该技术在聚合物膜上使用光声换能器；当换能器的声波在聚合物层内共振时，我们能够光学监测波的干涉，其模式是局部聚合物厚度的特征。光声模型被用来模拟换能器共振和聚合物腔模式的干扰，允许与实验进行比较，以便对样品区域内每个位置的聚合物腔长度进行反向工程。这种方法得到的厚度图与实验声频的变化非常相似，并且在10×10 mm的大样品上显示了≈200-500 nm的厚度梯度。通过利用千兆赫兹频率超声，该技术提供了获取聚合物薄膜纳米特征的途径，并可应用于薄膜的制备。
In this paper we present a method for characterizing the thickness, and more interestingly, the variation of thickness in polymer thin films (<1 µm). The technique utilizes an optoacoustic transducer atop the polymer film; as the transducer’s acoustic waves resonate within the polymer layer, we are able to optically monitor the interference of the waves, whose patterns are characteristic of the local polymer thickness. An optoacoustic model was used to simulate the interference of the transducer resonance and the polymer cavity modes, allowing a comparison with experiment in order to reverse engineer the polymer cavity length at each position across an area of the sample. This method yielded a thickness map which closely resembles the variation in experimental acoustic frequency, and indicated a thickness gradient of ≈200-500nm across the large 10×10mm sample. By utilizing Gigahertz frequency ultrasound, this technique provides access to nanometric features of polymer films and could be applied to film thickness monitoring applications within the field of polymer science.In this paper we present a method for characterizing the thickness, and more interestingly, the variation of thickness in polymer thin films (<1 µm). The technique utilizes an optoacoustic transducer atop the polymer film; as the transducer’s acoustic waves resonate within the polymer layer, we are able to optically monitor the interference of the waves, whose patterns are characteristic of the local polymer thickness. An optoacoustic model was used to simulate the interference of the transducer resonance and the polymer cavity modes, allowing a comparison with experiment in order to reverse engineer the polymer cavity length at each position across an area of the sample. This method yielded a thickness map which closely resembles the variation in experimental acoustic frequency, and indicated a thickness gradient of ≈200-500nm across the large 10×10mm sample. By utilizing Gigahertz frequency ultrasound, this technique provides access to nanometric features of polymer films and could be applied to film th...