Submicron-size patterning on the sapphire substrate prepared by nanosphere lithography and nanoimprint lithography techniques

In this paper, we demonstrate and compare the formation of ordered etching masks for submicron-size patterned sapphire substrates through use of the nanosphere lithography and nanoimprint lithography methods. The metal honeycomb network structure and the polymer pillar protrusion structure were obtained from these two methods. Subsequently, the inductively-coupled-plasma reactive ion etching technique was applied to etch the sapphire substrates, and the etchant mixture gases of boron trichloride and argon with the flow rate ratio of 1 to 6 were introduced into the etchant chamber. Two types of submicron -pattern structures were obtained on the sapphire substrate surface after the etching processes were completed. One type of sapphire substrate was the submicron hole array structure and another type was the submicron cone array structure. The working pressure had a considerable effect on the shape geometry and etching rate, and the possible mechanism is discussed.