A method and structure to form shallow trench isolation regions without trench
oxide grooving is provided. In particular, a method includes a two-step oxide process
in which an oxide liner lines the inside surface of a trench and the trench is
filled with a bulk oxide layer, preferably using a high density plasma chemical
vapor deposition (HDP-CVD) process. The oxide liner and the bulk oxide layer are
formed to have similar etch rates. Thus, when etching the oxide liner and the bulk
oxide layer between stack structures, a common dielectric top surface is formed
that is substantially planar and without grooves.
