GGNMOS叉指宽度与金属布线对ESD防护性能的影响

栅接地NMOS(GGNMOS)器件具有与CMOS工艺兼容的制造优势,广泛用于静电放电(ESD)保护。鉴于目前GGNMOS的叉指宽度、叉指数及金属布线方式等外部因素对ESD鲁棒性的影响研究较少,设计了不同的实验对此开展对比分析。首先,基于0.5μm Bipolar-CMOS-DMOS(BCD)工艺设计并制备了一系列GGNMOS待测器件;其次,通过传输线脉冲测试,分析了叉指宽度与叉指数对GGNMOS器件ESD失效电流(It2)的影响,结果表明,在固定总宽度下适当减小叉指宽度有利于提高It2;最后,比较了平行式与交错式两种金属布线方案对It2的影响,结果表明,平行式金属布线下GGNMOS器件的ESD鲁棒性更好。

Effects of Finger Width and Metal Routing of GGNMOS on ESD Protection

Gate-grounded NMOS(GGNMOS) devices have been widely used for electrostatic discharge(ESD) protection due to their manufacturing compatibility with CMOS process.However,relatively little research has been done for the effects of finger width,number of fingers and metal routing methods of GGNMOS on the ESD protection robustness.Experiments are thus designed to investigate the effects of these external factors by comparison.First,different GGNMOS devices are designed and fabricated based on the 0.5 μm Bipolar-CMOS-DMOS(BCD) process.Then,transmission line pulse testing is performed to analyze the effects of finger width and finger number on the ESD failure current(It2).The results indicate that for GGNMOS devices of fixed total width,decreasing the width of single finger reasonably helps to increase It2.Finally,the effects of the parallel and cross-patterned metal routing methods on the ESD failure current are investigated.The results suggest that GGNMOS devices with parallel metal routing have a better ESD robustness.