Through-wafer electrical interconnects by sidewall photolithographic patterning

This paper describes a new photolithography technique for patterning vertical surfaces using 45-degree reflective mirrors. The resolution is limited by diffraction and by surface scattering. Using this techniques, novel through-wafer interconnects have been demonstrated with high wiring density. At 320 nm wavelength, 50 μm-wide vertical lines have been fabricated with 25 μm line-width loss