In this paper, capacitors fabricated by an integrated passive device technology for isolated signal transfer applications are presented. The shapes of the capacitor plates are designed to achieve a symmetrical capacitive coupling matrix. Without using any highly doped shielding layer, the interference through the substrate can be eliminated in both forward and reverse directions for differential isolated signal transfer, regardless of the waveforms of the transmitter circuit. An isolation capacitor array with 3 channels and 700 fF capacitance values is experimentally demonstrated using a multilayer Cu/polyimide process. The capacitors show accurate capacitance values, 5kVrms isolation voltage and low leakage current of tens of pA at working voltage. Measurement results also show that the capacitor array with pseudo-symmetry reduces the mismatched interference signal by 5 times.

本文介绍了通过集成无源器件技术制造的，用于隔离信号传输应用的电容器。电容器极板的形状设计成实现对称的电容耦合矩阵。无需使用任何高掺杂的屏蔽层，就可以在正向和反向方向上消除通过基板的干扰，从而实现差分隔离信号传输，而与发送器电路的波形无关。使用多层铜/聚酰亚胺工艺实验证明了具有3个通道和700 fF电容值的隔离电容器阵列。这些电容器在工作电压下显示出准确的电容值，5kVrms的隔离电压和数十pA的低泄漏电流。