Abstract: This paper firstly introduces coupled capacity estimation，noise model choice and crosstalk noise estimation method.Then，a crosspoint assignment algorithm CPACNC （Crosspoint Assignment with Crosstalk Noise Control） for multilayer gridless area routing is thoroughly analyzed.The algorithm firstly decomposes the boundary of a tile to a set of internals by block information，and then solves CPA problem by two steps：Coarse Crosspoint Assignment（CCPA） and Detailed Crosspoint Assignment（DCPA）.When decomposing the boundary of a tile，CPACNC algorithm may generate lots of short internals.So this paper presents an amended algorithm to deal with this case，for making CPACNC algorithm more effective.

Key words: coupled capacity, crosstalk noise, crosspoint assignment, gridless routing

摘要： 首先介绍了耦合电容计算、噪声模型选择以及串扰噪声的估计，接着详细分析了一种用于多层无网格区域布线的过点分配算法CPACNC（Crosspoint Assignment with Crosstalk Noise Control）。该算法首先根据障碍物信息将小方块边界分成多个区段，再分两步解CPA问题：CCPA（Coarse Crosspoint Assignment）和DCPA（Detailed Crosspoint Assignment）。针对CPACNC算法在进行边界分解时可能产生许多碎段的缺点，最后提出了一种修正算法，以处理边界分解时产生许多碎段的情况，使CPACNC方法更加有效。

关键词: 耦合电容, 串扰噪声, 过点分配, 无网格布线