PCT-Cap: Point Cloud Transformer for Accurate 3D Capacitance Extraction

Accurate parasitic capacitance extraction becomes increasingly essential in advanced technology nodes. 2.5D ex-traction requires more effort to maintain accuracy comparable to the 3D solver. In this work, two experiments reveal that error deviation in the 2.5D method enlarges as wire width shrinks and length increases. A novel Gauss law-based point cloud is proposed to model the 3D capacitance problem. With the proposed data representation, a transformer-based neural network architecture, called PCT-Cap, is designed for 3D pattern matching. PCT-Cap exhibits much better performance than the ResNet-based capacitance models. Extensive experiments on 28nm technology demonstrate that PCT-Cap can accurately predict over 95.41 % of total capacitance with an error margin of less than 5 %. Additionally, PCT-Cap achieves 95.90 % accuracy in predicting coupling capacitance within a margin of error of less than 10%. PCT-Cap achieves at least a 55 × speeding up compared with the commercial extraction tool while consuming negligible memory.