synopsys的user guide里经常会看到small geometries是什么意思啊？
时间：10-02
整理：3721RD
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小的几何结构，是指现在先进到20nm一下工艺的意思?还是说layout里面具体到一段net，一个via的这种微小结构?我感觉好像是后者的意思吧，但是不是微电科班出身，在这求证下。
原文如下：
At small geometries, the RC coefficients, especially resistance coefficients, can vary
significantly between layers. In this case, the coefficients derived by averaging the
coefficients for all layers might not provide sufficient correlation with the postroute values.
You can restrict the set of routing layers used for a specific net by defining net-based
layer constraints.
原文如下：
At small geometries, the RC coefficients, especially resistance coefficients, can vary
significantly between layers. In this case, the coefficients derived by averaging the
coefficients for all layers might not provide sufficient correlation with the postroute values.
You can restrict the set of routing layers used for a specific net by defining net-based
layer constraints.
通常是小于65nm ，
谢谢小编！