Proxy delta lithography method: Improving pattern fidelity and exposure dose effectiveness of spatial light modulation based lithography

• A lithography method based on the proxy delta configuration is developed.
• The 99.9% honeycomb configuration is implemented using a square image array.
• The exposure dose effectiveness is increased through the proposed method.
• The potential for improving pattern fidelity is demonstrated by shape error analysis.

Optical mask-less lithography utilizing spatial light modulators, i.e., spatial light modulation based lithography, launched to resolve issues raised by using masks. Beams reflected off selected micromirrors on a spatial light modulator are irradiated onto a translating substrate for lithographic patterning. To improve pattern fidelity and exposure dose effectiveness, a novel lithography method based on the proxy delta configuration is developed. For practical applications of the honeycomb configuration using an existing square image array without the difficulty of projecting a square mirror array into a rectangular image array, proxy delta configuration parameters for a honeycomb structure, made up of six triangles that are precise enough to be considered equilateral, are proposed. To verify the proposed method and parameters, lithography simulations are performed using Gaussian and partially coherent beams. In comparison with the existing square configuration, the proxy delta configuration results in better exposure dose effectiveness which may lead to reduced luminance differences. The potential for improving pattern fidelity through the proposed method using an existing square image array is demonstrated by the critical shape error measurements.

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