Fabrication of Subwavelength Metallic Structures Using Laser Interference Lithography

Laser interference lithography technique was adopted to fabricate subwavelength metallic structures. One-dimensional (ID) grating structures, two-dimensional (2D) grid patterns, and 2D particles array were obtained on the photoresist film by means of direct exposing the resist using the interference patterns. Then the photoresist patterns were transferred to the quartz substrate by wet etching and reactive ion etching with CHF3/O2 as etchants. Finally, the metal material were deposited on the quartz. Atomic force microscope (AFM) was employed for geometrical characterization of the patterns generated in the steps from pattern generation to pattern transfer respectively. Results have shown that ID and 2D structures, with feature size of 150nm and average period of 300nm have been gained. The exposure method has advantages of mask free, cost effective, and good controllability with great efficiency and speed.The subwavelength metallic structures are acceptable for the applications of surface plasmon resonance (SPR)-based biosensing and applicable for fabrication of nanoimprint stamps with large areas.