Netherlands Organization for Applied Scientific Research (T.N.O.), Postbus 155, 2600AD Delft, The Netherlands.
Langmuir. 2011 Sep 20;27(18):11430-5. doi: 10.1021/la2010776. Epub 2011 Aug 17.
It is the aim of this paper to quantitatively characterize the capability of surface nanobubbles for surface cleaning, i.e., removal of nanodimensioned polystyrene particles from the surface. We adopt two types of substrates: plain and nanopatterned (trench/ridge) silicon wafer. The method used to generate nanobubbles on the surfaces is the so-called alcohol-water exchange process (use water to flush a surface that is already covered by alcohol). It is revealed that nanobubbles are generated on both surfaces, and have a remarkably high coverage on the nanopatterns. In particular, we show that nanoparticles are-in the event of nanobubble occurrence-removed efficiently from both surfaces. The result is compared with other bubble-free wet cleaning techniques, i.e., water rinsing, alcohol rinsing, and water-alcohol exchange process (use alcohol to flush a water-covered surface, generating no nanobubbles) which all cause no or very limited removal of nanoparticles. Scanning electron microscopy (SEM) and helium ion microscopy (HIM) are employed for surface inspection. Nanobubble formation and the following nanoparticle removal are monitored with atomic force microscopy (AFM) operated in liquid, allowing for visualization of the two events.
本文旨在定量描述纳米气泡的表面清洁能力，即从表面去除纳米级聚苯乙烯颗粒。我们采用了两种类型的衬底：普通硅片和纳米图案化（沟槽/脊）硅片。在表面生成纳米气泡采用的方法是所谓的酒精-水交换过程（用水冲洗已经被酒精覆盖的表面）。结果表明，纳米气泡在两种表面上都能生成，并且在纳米图案上的覆盖率非常高。特别是，我们表明在纳米气泡存在的情况下，颗粒能够有效地从两种表面上被去除。这一结果与其他无泡湿法清洁技术（如用水冲洗、用酒精冲洗和水-酒精交换过程（用酒精冲洗被水覆盖的表面，不生成纳米气泡）进行了比较，这些技术都不能或只能有限地去除颗粒。扫描电子显微镜（SEM）和氦离子显微镜（HIM）被用于表面检查。纳米气泡的形成和随后的纳米颗粒的去除用液体环境下的原子力显微镜（AFM）进行监测，允许可视化这两个过程。
