Investigation of particle induced template damage and proposal of mitigation

Nanoimprint lithography (NIL) has potential as a low-cost fabrication process for fine patterning of semiconductor devices. However, there are issues like the template life that restricts cost reduction further. Quartz template for NIL is prone to permanent damage when it contacts particles causing lower template life and higher template cost per imprinted wafer. This study reveals that the template is damaged due to the shear force exerted on the template by the particles. Extent of template damage depends on the young`s modulus of the particle. Residual layer thickness (RLT) has effect on mitigating particle induced template damage. The hard-most aluminum oxide particle that has been investigated in this study, has a critical particle height (CPH) i.e., the minimum particle height over which the particle causes template damage, of 126 nm when the RLT is 25 nm. Furthermore, CPH is found to be affected by the template design namely, pattern width of the pattern. For the same particle and template design, the CPH is reduced with thicker RLT. In other words, NIL process with thicker RLT is preferred for containing template damage. Based on these results, we conclude that the particle management and process optimization (RLT, stack) considering the template design and device nodes are important to minimize template damage and increase cost benefit from NIL.