Microscope projection photolithography based on ultraviolet light-emitting diodes

We adapted a conventional microscope for projection photolithography using an ultraviolet (UV) light-emitting diode (LED) as a light source. The use of a UV LED provides the microscope projector with several advantages in terms of compactness and cost. The adapted microscope was capable of producing line patterns as wide as 5 μm with the use of a 4X objective lens under optimal lithography conditions. The obtained line width is close to that of the diffraction limit, implying that the line width can be reduced further with the use of a higher resolution photomask and higher magnification objective lens. Finally, we showed how the single slit fabricated by microscope projection photolithography was used for a diffraction experiment. We expect that low-cost microscope projection photolithography based on a UV LED will contribute to the field of physics education or various areas of research, such as chemistry and biology, in the future.