高耐压LDMOS用的高K薄膜湿法刻蚀研究

Research on Wet Etching of High-K Thin Films Used in the LDMOS Power Devices

为了对横向双扩散MOSFET(LDMOS)器件所采用的锆钛酸铅(PZT)高介电常数(高K)薄膜进行微图形化,对湿法刻蚀过程中腐蚀液、光刻、刻蚀等工艺进行了优化研究,发现由BOE+HCl+HNO3+H2O+缓冲剂组成的腐蚀液刻蚀效果较好。刻蚀结果表明,所刻蚀薄膜的厚度约为600nm,最小线条宽度约为3μm,侧蚀比减小到1.07∶1,符合功率器件制备的尺度要求,由此所制备的LDMOS器件耐压提高了近2倍。

For the micro-pattern study of high permittivity（high-K） thin films PZT used in high voltage LDMOS power devices,the etching solution,lithography and etching process parameters of the wet etching technique had been optimized.The etching solution composed of BOE＋HCl＋HNO3＋H2O＋buffer owned preferably etching effect.The tested result showed that the smallest etched lines of PZT films were about 600 nm thick,3 μm wide,and lateral erosion ratio was reduced to 1.07∶1,which met the requirements of power device fabrication requirements.The breakdown voltage of the LDMOS device with high-K thin films has been increased nearly 2-fold.