Saalmink Milan, van der Marel Cees, Stapert Henk R, Burdinski Dirk
Philips Research, High Tech Campus Eindhoven, 5656 AE Eindhoven, The Netherlands.
Langmuir. 2006 Jan 31;22(3):1016-26. doi: 10.1021/la052513v.
The soft lithographic replication of patterns with a low filling ratio by microcontact printing (microCP) is problematic due to the poor mechanical stability of common elastomeric stamps. A recently described strategy to avoid this problem employs a modified patterning method, positive microcontact printing ((+)microCP), in which a stamp with a mechanically more stable inverted relief pattern is used. In contrast to conventional negative microCP ((-)microCP), in the contact areas a self-assembled monolayer (SAM) is printed of a "positive ink", which provides only minor etch protection, whereas the noncontacted areas are subsequently covered with a different, etch-resistant SAM, prior to development by chemical etching. With the aim to identify novel, highly versatile positive inks, the patterning of gold by (+)microCP with mercaptoalkyloligo(ethylene glycol)s (MAOEGs), the subsequent adsorption of octadecanethiol (ODT), and the final development by wet chemical etching have now been studied. A polydisperse mixture of mercaptoundecylocta(ethylene glycol) derivatives was found to provide the best patterning results. The surface spreading of the positive ink during stamping, the exchange of printed MAOEGs with ODT, and the choice of the right etching bath were identified as key parameters that influence the achievable pattern resolution and contrast. Due to the modular composition of functionalized alkyloligo(ethylene glycol) derivatives, (+)microCP with these positive inks has the potential for easy adaptation to a variety of materials and development conditions.
通过微接触印刷（microCP）对低填充率图案进行软光刻复制存在问题，因为普通弹性印章的机械稳定性较差。最近描述的一种避免此问题的策略采用了一种改进的图案化方法，即正性微接触印刷（(+)microCP），其中使用具有机械稳定性更高的倒置浮雕图案的印章。与传统的负性微接触印刷（(-)microCP）相比，在接触区域印刷的是一种“正性墨水”的自组装单层（SAM），它仅提供轻微的蚀刻保护，而在通过化学蚀刻显影之前，未接触的区域随后会覆盖不同的抗蚀刻SAM。为了确定新型的、高度通用的正性墨水，现在研究了用巯基烷基低聚乙二醇（MAOEGs）通过(+)microCP对金进行图案化、随后吸附十八烷硫醇（ODT）以及最终通过湿化学蚀刻进行显影的过程。发现巯基十一烷基八聚乙二醇衍生物的多分散混合物能提供最佳的图案化效果。正性墨水在压印过程中的表面铺展、印刷的MAOEGs与ODT的交换以及合适蚀刻液的选择被确定为影响可实现的图案分辨率和对比度的关键参数。由于功能化烷基低聚乙二醇衍生物的模块化组成，使用这些正性墨水进行(+)microCP有潜力轻松适应各种材料和显影条件。
