4 April 2011 Double and triple exposure with image reversal in a single photoresist layer
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The current photolithography technology is approaching the physical barrier to the minimum achievable feature size. To produce smaller devices, new resolution enhancement technologies must be developed. Double exposure lithography has shown promise as a potential pathway that is attractive because it is much cheaper than double patterning lithography and it can be deployed on existing imaging tools. Double patterning uses two photoresist layers to transfer the final pattern to a hard mask layer. This paper proposes a novel double exposure patterning method that combines two consecutive exposures of mask patterns with an intermediate image reversal processing step in a single photoresist layer. The proposed method has a low cost-of-ownership, since only one photoresist layer is used. Using simple "primitive" mask patterns for the various exposures, the method produces complex patterns that cannot be achieved by conventional double exposure methods. This approach mitigates also the diffraction distortion effects of inside corners present particularly in highly regular lithography patterns. In case of triple exposure, the diffraction rounding of the outside corners can be mitigated as well. This approach can be retrofitted into existing older photolithography generations, obviating in many cases the use of optical proximity corrections and thus boosting the yields significantly.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Coumba Ndoye, Coumba Ndoye, Marius Orlowski, Marius Orlowski, } "Double and triple exposure with image reversal in a single photoresist layer", Proc. SPIE 7970, Alternative Lithographic Technologies III, 79701H (4 April 2011); doi: 10.1117/12.879505; https://doi.org/10.1117/12.879505

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