**4.2 EB drawing and sample preparation**

The conventional EB drawing system was used as described in section 3. 1. The drawing was done on a resist layer coating on a piece of Si after we set the sample on the XY table in the system. The EB drawing was done under a probe current of 100 pA at an acceleration voltage of 30 kV. In the other system parameters, the address resolution was 2.5 nm in a drawing field of 25 µm x 25 µm.

The calixarene resist films on Si substrate with a thickness of 11.8 nm to 16.9 nm, which were controlled by the spin coating at a speed of 3000 rpm to 8000 rpm for 190 s was prepared as shown in Fig. 4. 3. The thicknesses were measured by contact mode atomic force microscope (AFM).

The resist process is as follows. After coating the resist on the Si substrate, pre-baking was done at the 110 oC for 3 min in air. Then, the EB drawing was done by raster scanning with the CAD data. After the developing and rinsing with a developer of ZEP-RD and isopropanol, respectively, The pattern quality was checked whether complete formation of the drawn dot arrays was done or not.

Fig. 4.3. Thicknesses of 11.8 nm to 16.9 nm controlled by the spin coating at a speed of 3000 rpm to 8000 rpm
