**5. Application of EB drawing to formation of nano-Si-dot and nano-polymerpit arrays with a pitch of 25 nm x 25 nm using EB drawing, reactive ion etching (RIE) and nano-imprinting [23, 25]**

The possibility of forming very fine pits or dots with a pitch of less than 25 nm was researched using reactive ion etching (RIE) and nano-imprinting with EB drawn pattern as a mask for the future process. We were able to fabricate ultrahighly packed dot arrays with a dot diameter of less than 15 nm and a dot pitch of 25 nm x 25 nm in negative calixarene resist using EB drawing. We also formed nan-Si dot arrays patterns by CF4 RIE. Furthermore, pit arrays were formed in polymer film through nano-imprinting by the photo-polymer method using a Si dot arrays pattern as the master mold. We demonstrated that the EB-drawn dot arrays resist pattern is very suitable for the fabrication of Si dot arrays and pit arrays with a pitch of 25 nm x 25 nm in this polymer. The Si dot and pit diameters were less than 10 nm.

Fig. 5.1. Process flow for Si nano-dot arrays by RI etching and ashing.
