We investigated a new method for decrease of CD disparity due to fogging effect at photomask making, utilizing side-wall-angle-dependence of CD loss through descum process. We demonstrated this method could be valid for less than half-micron. This method can be effective on condition of anisotropic descum, no "foot" at post- descum, and just- or under-development. Using this method, we obtained CD uniformity of 18.6nm (3 sigma , 132mm square) over fogging and non-foggingfield, including process error.
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