Organosilane Self-Assembled Thin Resist Films for Nanoprocessing

1)基于气相自组装的超薄抗蚀膜的制备采用化学气相沉积法制备了有机硅烷自组装单层膜（SAM）。在形成SAM之前，利用真空紫外光产生的氧自由基对衬底进行光化学清洁。SAMs是气相形成的。这种方法在涂布和冲洗时都不需要溶剂。2) SAM电阻的化学电阻率为了阐明SAM可以用作蚀刻掩膜，研究了SAM在氢氟酸中湿法蚀刻和fry蚀刻下的化学电阻率。尽管其厚度小于2nm，但sam对蚀刻物表现出优异的电阻率。利用SAMs掩模，等离子体刻蚀可制备50 nm深的沟槽。3)成功地将厚度小于2nm的烷基硅烷SMA应用于vv光刻和扫描探针光刻的抗蚀剂。光掩膜的图像是通过SAM的光分解作用印在SAM上的。另一方面，由于其在原子力显微镜探针尖端下局部诱导的电化学降解，在SAM上写入了原子力显微镜探针的扫描图案。这些微纳米尺度的图案可以通过湿化学蚀刻或干等离子体蚀刻转移到硅衬底上。目前，光刻和扫描探针光刻分别制备了最小宽度为2000 nm和20 nm的特征。此外，我们还展示了基于注入电流的原子力显微镜光刻技术的绝缘体纳米结构。采用具有导电性的多层抗蚀膜。该抗蚀剂由三层组成，即a-Si、其光化学氧化物和SAM，厚度分别为20nm、2nm和2nm。纳米尺度的模式首先由原子力显微镜在SAM中定义。然后通过两步抗蚀剂显影过程将这些图案转移到a-Si层中。最后，利用所制备的抗蚀剂作为蚀刻掩膜，对衬底SiO2进行纳米结构。少

1) Preparation of ultra-thin resist films based on vapor phase self-assemblyOrganosilane self-assembled monolayers (SAM) have been prepared by a chemical vapor deposition method. Prior to the SAM formation, substrates were photochemically cleaned using vacuum ultra-violet light generated oxygen radicals. The SAMs were formed in vapor phase. This method requires no solvent both for coating and rinsing. Thickness of the SAM-resists could be controlled in the range of 0.2 - 2.0 nm.2) Chemical resistivity of the SAM resistsIn order to elucidate that the SAMs can be used as etching masks, chemical resistivity of the SAMs to wet etching in hydrofluoric acid and fry etching were studied. The SAMs have been found to show excellent resistivities to the etchings, although their thickness were less than 2nm. By using the SAMs mask, 50 nm deep trenches could be fabricated by the plasma etching.3) Lithography using SAM resistAn alkylsilane SMA less than 2 nm in thickness has been successfully appli … More ed to the resist for VUV-photolithography and scanning probe lithography. The image of a photomask was printed on the SAM through its photodecomposition. On the other hand, an AFM-probe scanning pattern was written on the SAM due to its electrochemical degradation locally induced beneath the AFM-probe tip. These micro or nano-scale pattern could be transferred into the Si substrates by wet chemical etching or dry plasma etching. At present, features of minimum width of 2000 nm and 20 nm were fabricated by photolithography and the scanning probe lithography, respectively.In addition, we have demonstrated nanostructuring of insulator based on the current-injecting AFM-lithography. A multilayered resist film with electrical conductivity was employed. This resist consisted of triple layers, that is, a-Si, its photochemical oxide and SAM with thicknesses of 20, 2 and 2 nm, respectively. Nanoscale patterns were first defined by AFM in the SAM. These patterns were then transferred into the a-Si layer through the 2-step resist developing process. Finally, the substrate SiO2 was nanostructured using the developed resist as an etching mask. Less