Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL 62901, USA.
GSI Helmholtzzentrum, 64291 Darmstadt, Germany.
Sci Adv. 2017 Jun 9;3(6):e1602071. doi: 10.1126/sciadv.1602071. eCollection 2017 Jun.
A new lithographic editing system with an ability to erase and rectify errors in microscale with real-time optical feedback is demonstrated. The erasing probe is a conically shaped hydrogel (tip size, ca. 500 nm) template-synthesized from track-etched conical glass wafers. The "nanosponge" hydrogel probe "erases" patterns by hydrating and absorbing molecules into a porous hydrogel matrix via diffusion analogous to a wet sponge. The presence of an interfacial liquid water layer between the hydrogel tip and the substrate during erasing enables frictionless, uninterrupted translation of the eraser on the substrate. The erasing capacity of the hydrogel is extremely high because of the large free volume of the hydrogel matrix. The fast frictionless translocation and interfacial hydration resulted in an extremely high erasing rate (785 μm/s), which is two to three orders of magnitude higher in comparison with the atomic force microscopy-based erasing (0.1 μm/s) experiments. The high precision and accuracy of the polymeric lithography editor (PLE) system stemmed from coupling piezoelectric actuators to an inverted optical microscope. Subsequently after erasing the patterns using agarose erasers, a polydimethylsiloxane probe fabricated from the same conical track-etched template was used to precisely redeposit molecules of interest at the erased spots. PLE also provides a continuous optical feedback throughout the entire molecular editing process-writing, erasing, and rewriting. To demonstrate its potential in device fabrication, we used PLE to electrochemically erase metallic copper thin film, forming an interdigitated array of microelectrodes for the fabrication of a functional microphotodetector device. High-throughput dot and line erasing, writing with the conical "wet nanosponge," and continuous optical feedback make PLE complementary to the existing catalog of nanolithographic/microlithographic and three-dimensional printing techniques. This new PLE technique will potentially open up many new and exciting avenues in lithography, which remain unexplored due to the inherent limitations in error rectification capabilities of the existing lithographic techniques.
一种具有实时光学反馈功能的微尺度纠错能力的新型光刻编辑系统得到了展示。擦除探针是一种由锥形玻璃晶片刻蚀而成的锥形水凝胶（尖端尺寸约为 500nm）模板合成的。“纳米海绵”水凝胶探针通过扩散将分子水化并吸收到多孔水凝胶基质中，从而“擦除”图案，类似于湿海绵。在擦除过程中，水凝胶尖端与基底之间存在界面液态水层，使得橡皮擦能够在基底上无摩擦、不间断地平移。由于水凝胶基质的大自由体积，水凝胶的擦除能力极高。快速无摩擦的平移和界面水化导致极高的擦除速率（785μm/s），与基于原子力显微镜的擦除实验（0.1μm/s）相比，高出两个数量级。聚合物光刻编辑（PLE）系统的高精度和准确性源于将压电致动器与倒置光学显微镜耦合。随后，在用琼脂糖橡皮擦擦除图案后，使用相同的锥形轨迹刻蚀模板制造的聚二甲基硅氧烷探针用于精确地在擦除点重新沉积感兴趣的分子。PLE 还在整个分子编辑过程（写入、擦除和重写）中提供连续的光学反馈。为了展示其在器件制造中的潜力，我们使用 PLE 电化学擦除金属铜薄膜，形成用于制造功能微光电探测器器件的微电极交错阵列。高通量点和线擦除、锥形“湿纳米海绵”的写入以及连续的光学反馈使 PLE 成为现有纳米光刻/微光刻和三维打印技术的补充。由于现有光刻技术在纠错能力方面的固有局限性，这种新的 PLE 技术将有可能在光刻领域开辟许多新的令人兴奋的途径。
