Effect of Polymer Substrates on Nano Scale Hot Embossing
- PDF / 195,677 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 106 Downloads / 210 Views
A5.50.1
Effect of Polymer Substrates on Nano Scale Hot Embossing Jin-Hyung Lee1, Hyun-Woo Lim 2, Jin-Goo Park1, Eun-Kyu Lee2 and Yangsun Kim2* 1 Dept. of Metallurgy and Materials Eng., Hanyang University, Ansan, 425-791, Korea 2 Micro Biochip Center, Gyeonggi Techno park, Pilotplant-2 #104, Ansan, 462-901, Korea ABSTRACT Hot embossing has been widely accepted as an alternative to photolithography in generating patterns on polymer substrates. The optimization of embossing process should be accomplished based on polymer surface properties. Therefore, in this paper, polymers with different surface characteristic were selected and the surface properties of each polymers such as surface energy and adhesion force were investigated by contact angle and AFM. Based on these results, the imprinted nano patterns were compared. Silicon molds with nano size patterns were fabricated by e-beam direct writing. Molds were coated with self-assembled monolayer (SAM) of (1, 1, 2, 2H –perfluorooctyl)-trichlorosilane to reduce the stiction between molds and polymer substrates. For embossing, pressure of 500 psi, embossing time of 5 min and temperature of above transition temperature were applied. Mr-I 8010 polymer (Micro Resist Technology), Polymethylmethacrylate (PMMA 495k) and LOR (polyaliphatic imide copolymer) were used as substrate for hot embossing process development in nano size. These polymers were spun coated on the Si wafer with the thickness of 150 nm. The nano size patterns obtained by hot embossing were identified by atomic force microscopy without breaking the pattern and compared based on the polymer surface properties. The mr-I 8010 which has the lowest surface energy and adhesion force shows the best demolding property. 1. INTRODUCTION Nano-imprinting technologies are relatively low-cost method to demonstrate polymer microstructures as well as nano scale patterns. Especially, these technologies can be applied in nano scale pattern where optical lithography reaches its limit. Among them, hot embossing has the advantage of low-cost and biocompatible fabrication process over conventional nanofabrication method. A major issue in nanoimprint approach, particularly in hot embossing technique, is reproducibility of the printed results. An important prerequisite for reproducibility is to avoid sticking of the resist to the surface of the mold after detachment. To avoid stiction problems, surface modification of mold for antistiction is required and the surface characteristics of resist should be identified. Therefore, the surface characteristics of resist as well as mold surface modification, which ensure low surface energies[1] and low adhesion force at the mold/resist interface, minimizing the interaction between mold and resist during the imprint process, have been investigated. These surface properties make it possible to predict the mold result. In general, contact angle is a method to obtain the surface energy in large scale and AFM is a method to understand the surface in micro scale. Therefore, hot embossing technique
Data Loading...
