van Es Maarten H, Mohtashami Abbas, Thijssen Rutger M T, Piras Daniele, van Neer Paul L M J, Sadeghian Hamed
NOMI, Optomechatronics, TNO, Stieltjesweg 1, 2628CK, Delft, The Netherlands.
NOMI, Optomechatronics, TNO, Stieltjesweg 1, 2628CK, Delft, The Netherlands.
Ultramicroscopy. 2018 Jan;184(Pt A):209-216. doi: 10.1016/j.ultramic.2017.09.005. Epub 2017 Sep 23.
Nondestructive subsurface nanoimaging of buried nanostructures is considered to be extremely challenging and is essential for the reliable manufacturing of nanotechnology products such as three-dimensional (3D) transistors, 3D NAND memory, and future quantum electronics. In scanning probe microscopy (SPM), a microcantilever with a sharp tip can measure the properties of a surface with nanometer resolution. SPM combined with ultrasound excitation, known as ultrasound SPM, has shown the capability to image buried nanoscale features. In this paper, the development of a modified type of ultrasound SPM called subsurface ultrasonic resonance force microscopy (SSURFM) is reported. The capability and versatility of this method is demonstrated by the subsurface imaging of various samples including rigid structures buried under a soft matrix (aluminum under a polymer), rigid structures buried under multiple layers (aluminum under a polymer and titanium layer), and rigid structures under a rigid matrix (aluminum under silicon oxide). Furthermore, tuning and optimization of the image contrast are reported. The experimental results provide possible new industrial metrology and inspection solutions for nanostructures buried below the surface.
对埋藏纳米结构进行非破坏性的亚表面纳米成像被认为极具挑战性，而对于诸如三维（3D）晶体管、3D NAND存储器以及未来量子电子学等纳米技术产品的可靠制造而言，这又是至关重要的。在扫描探针显微镜（SPM）中，带有尖锐尖端的微悬臂梁能够以纳米分辨率测量表面特性。SPM与超声激发相结合，即所谓的超声SPM，已展现出对埋藏纳米级特征进行成像的能力。本文报道了一种改进型超声SPM——亚表面超声共振力显微镜（SSURFM）的研发情况。该方法的能力和通用性通过对各种样品的亚表面成像得以证明，这些样品包括埋在软质基体（聚合物下的铝）之下的刚性结构、埋在多层之下（聚合物和钛层下的铝）的刚性结构以及刚性基体（氧化硅下的铝）下的刚性结构。此外，还报道了图像对比度的调整与优化。实验结果为埋藏于表面以下的纳米结构提供了可能的新型工业计量和检测解决方案。
