Methods are disclosed for performing charged-particle-beam (CPB, e.g., electron-beam) microlithography with reduced Coulomb effects being manifest in pattern images as formed on the surface of a sensitive substrate. The pattern is defined on a segmented reticle, which can be a scattering-stencil reticle or scattering-membrane reticle. In an embodiment, the beam current actually reaching the substrate, as a proportion of beam current actually passing through the reticle, is reduced to 50% or less during exposure of the pattern. To achieve this reduction, the pattern as defined on the reticle can be normal or inverted in tone as required, and the resist on the substrate can be positive or negative in tone as required. In an example embodiment, the beam current reaching the substrate is reduced by establishing an opening ratio of 50% or less for the pattern as a whole as defined on the reticle. The opening ratio is expressed as 100[Aws/(Aws+Ahs)], wherein Ahs is a total area of the reticle occupied by both the weakly scattering reticle membrane and the highly scattering layer, and Aws is a total area of the reticle occupied by only the weakly scattering reticle membrane.
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机译：公开了用于执行带电粒子束（CPB，例如电子束）微光刻的方法，其中，库仑效应的降低在图案图像中表现出来，该图案图像形成在敏感基板的表面上。该图案被限定在分段的掩模版上，该掩模版可以是散射模版掩模版或散射膜掩模版。在一个实施例中，在图案的曝光期间，实际到达衬底的束电流，作为实际通过掩模版的束电流的比例，被减小到50％或更少。为了实现这种减小，在掩模版上定义的图案可以根据需要是正常的或色调反转的，并且在基板上的抗蚀剂可以根据需要的色调是正的或负极的。在示例实施例中，通过为掩模版上限定的整个图案建立50％或更小的开口率来减小到达基板的束电流。开口率表示为100＆lqb; A ws /（A ws ＆plus; A hs ）＆rsqb ;，其中A hs < / Sub>是被弱散射掩模版膜和高散射层都占据的掩模版的总面积，而A ws 是仅被弱散射掩模版膜所占据的掩模版的总面积。
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