Hybrid phase and amplitude modulation proximity printing mask fabricated on DLC and SiO2 substrates

A hybrid phase and amplitude modulation proximity printing mask was designed, manufactured and tested. The proposed diffractive structure modulates both the phase and the amplitude of a UV exposure beam. In the fused silica substrate a relief is generated in order to modulate the phase and a patterned diamond like carbon layer modulates the amplitude of the UV light. Besides, the diamond like carbon thin film is partially transparent at wavelengths larger than 400 nm, what improves the alignment procedures between different mask levels. The lithographic image was projected onto a resist coated silicon wafer, placed at a distance of 50 micrometer behind the mask, obtaining a resolution better than 1 micrometer, what is impossible with traditional proximity printing techniques.