A new dummy-free shallow trench isolation concept for mixed-signal applications

Shallow trench isolation (STI) is becoming the mainstream lateral isolation module for deep submicrometer technologies. It is generally accepted that dummy active areas need to be implemented due to the limited within-chip un iformity associated with the chemical mechanical polishing step. Dummy acti ve areas, however, are problematic when used in mixed-signal technologies d ue to the increased capacitive coupling and noise associated with them. To solve this problem, we developed an STI module that ensures minimum oxide d ishing and nitride erosion without the need for dummy active areas. This pa per presents and discusses the fabrication process for this STI module and the results obtained with it. We have successfully implemented the new dumm y-free STI process in a 0.18 mu m technology. (C) 2000 The Electrochemical Society. S0013-1651(00)02-027-9. All rights reserved.