Deep subwavelength photolithography based on surface plasmon polariton resonance with metallic grating waveguide heterostructure

Deep subwavelength photolithography with a metallic grating waveguide heterostructure (MGWHS) is presented and numerically demonstrated by a finite-difference time-domain method. This lithography scheme is demonstrated by interference between the diffracted waves of the mask which are enhanced by the surface plasmon polariton (SPP) resonance in this MGWHS. The relationship between the pattern resolution and the thickness of the photoresist is discussed. With proper choices of the dimensions of the proposed MGWHS and the illumination light, either a deep subwavelength (similar to lambda/17) pattern with sufficient contrast or a high quality interference pattern can be achieved. This approach is suitable for application to deep subwavelength photolithography without expensive equipment.